query: the number of electrons in the innermost shell of lithium ( atomic number 3 )

pos: Electron shell found to correspond to the "n" values 1, 2, 3, etc. They are used in the spectroscopic Siegbahn notation. The physical chemist Gilbert Lewis was responsible for much of the early development of the theory of the participation of valence shell electrons in chemical bonding. Linus Pauling later generalized and extended the theory while applying insights from quantum mechanics. The electron shells are labeled K, L, M, N, O, P, and Q; or 1, 2, 3, 4, 5, 6, and 7; going from innermost shell outwards. Electrons in outer shells have higher average energy and travel farther from the nucleus

pos: Effective atomic number interactions. For instance, lithium, atomic number 3, has two electrons in the 1s shell and one in the 2s shell. Because the two 1s electrons screen the protons to give an effective atomic number for the 2s electron close to 1, we can treat this 2s valence electron with a hydrogenic model. Mathematically, the effective atomic number Z can be calculated using methods known as "self-consistent field" calculations, but in simplified situations is just taken as the atomic number minus the number of electrons between the nucleus and the electron being considered. An alternative definition of the effective atomic number

pos: Aufbau principle number, one electron is added each time to the atom. The maximum number of electrons in any shell is "2n", where "n" is the principal quantum number. The maximum number of electrons in a subshell (s, p, d or f) is equal to 2(2ℓ+1) where ℓ = 0, 1, 2, 3... Thus these subshells can have a maximum of 2, 6, 10 and 14 electrons respectively. In the ground state the electronic configuration can be built up by placing electrons in the lowest available orbitals until the total number of electrons added is equal to the atomic number. Thus orbitals

pos: Siegbahn notation atomic number. For example, K-alpha for iron (Z = 26) is calculated in this fashion as 10.2 eV (25) = 6.38 keV energy. For astrophysical purposes, Doppler and other effects (such as gravitational broadening) show the iron line to no better accuracy than 6.4 keV. K-beta emissions, similar to K-alpha emissions, result when an electron transitions to the innermost "K" shell (principal quantum number 1) from a 3p orbital of the third or "M" shell (with principal quantum number 3). Values can be found in the X-Ray Transition Energies Database. , Siegbahn notation The Siegbahn notation is used in X-ray

pos: Spin quantum number a point. The shell numbers start at 1 and increase indefinitely. Each shell of number contains ² orbitals. Each orbital is characterized by its number , where takes integer values from "0" to −1, and its angular momentum number , where takes integer values from + to −. By means of a variety of approximations and extensions, physicists were able to extend their work on hydrogen to more complex atoms containing many electrons. Atomic spectra measure radiation absorbed or emitted by electrons "jumping" from one "state" to another, where a state is represented by values of , , and .

pos: Azimuthal quantum number all atoms so far discovered. For a given value of the principal quantum number "n", the possible values of "ℓ" range from 0 to "n" − 1; therefore, the "n" = 1 shell only possesses an s subshell and can only take 2 electrons, the "n" = 2 shell possesses an s and a p subshell and can take 8 electrons overall, the "n" = 3 shell possesses s, p, and d subshells and has a maximum of 18 electrons, and so on. Generally speaking, the maximum number of electrons in the "n"th energy level is 2"n". The angular momentum

pos: Electron shell found to correspond to the "n" values 1, 2, 3, etc. They are used in the spectroscopic Siegbahn notation. The physical chemist Gilbert Lewis was responsible for much of the early development of the theory of the participation of valence shell electrons in chemical bonding. Linus Pauling later generalized and extended the theory while applying insights from quantum mechanics. The electron shells are labeled K, L, M, N, O, P, and Q; or 1, 2, 3, 4, 5, 6, and 7; going from innermost shell outwards. Electrons in outer shells have higher average energy and travel farther from the nucleus

pos: Quantum number outermost valence electrons of the Carbon (C) atom, which are located in the 2p atomic orbital, are; "n" = 2 (2nd electron shell), "" = 1 (p orbital subshell), "m" = 1, 0 or −1, "m" = ½ (parallel spins). Results from spectroscopy indicated that up to two electrons can occupy a single orbital. However two electrons can never have the same exact quantum state nor the same set of quantum numbers according to Hund's rules, which addresses the Pauli exclusion principle. A fourth quantum number with two possible values was added as an "ad hoc" assumption to resolve the

pos: Bohr model and these orbit at Z=2. Each one sees the nuclear charge of Z=3 minus the screening effect of the other, which crudely reduces the nuclear charge by 1 unit. This means that the innermost electrons orbit at approximately 1/4 the Bohr radius. The outermost electron in lithium orbits at roughly Z=1, since the two inner electrons reduce the nuclear charge by 2. This outer electron should be at nearly one Bohr radius from the nucleus. Because the electrons strongly repel each other, the effective charge description is very approximate; the effective charge Z doesn't usually come out to be an

pos: Period 1 element modern theories of atomic structure. In a quantum mechanical description of atomic structure, this period corresponds to the filling of the 1s orbital. Period 1 elements obey the duet rule in that they need two electrons to complete their valence shell. The maximum number of electrons that these elements can accommodate is two, both in the 1s orbital. Therefore, period 1 can have only two elements. All other periods in the period table contain at least 8 elements, and it is often helpful to consider periodic trends across the period. However, period 1 contains only two elements, so this concept

pos: Periodic matrix set written as; 2E/ћω. The rings may also be associated with atomic orbitals. If the ring number (n) is equal to the quantum number for orbital angular momentum (the azimuthal number l ), then the rings (0, 1, 2, 3) correspond to the orbitals (s, p, d, f). The ring number is NOT equal to the principal quantum number (n ). The number of cells per ring is half the number of electrons per orbital due to spin duality of the electrons. The quantum numbers are; n is the principal quantum numberl is the quantum number for orbital angular momentum (the

pos: Electron configuration spin, one with a spin +1/2 (usually denoted by an up-arrow) and one with a spin −1/2 (with a down-arrow). A subshell is the set of states defined by a common azimuthal quantum number, ℓ, within a shell. The values ℓ = 0, 1, 2, 3 correspond to the "s", "p", "d", and "f" labels, respectively. For example, the 3"d" subshell has n = 3 and ℓ = 2. The maximum number of electrons that can be placed in a subshell is given by 2(2ℓ+1). This gives two electrons in an s subshell, six electrons in a p subshell, ten

pos: Period 2 element description of atomic structure, this period corresponds to the filling of the 2s and 2p orbitals. Period 2 elements obey the octet rule in that they need eight electrons to complete their valence shell. The maximum number of electrons that these elements can accommodate is ten, two in the 1s orbital, two in the 2s orbital and six in the 2p orbital. Period 2 is the first period in the periodic table that periodic trends can be drawn from. Period 1, which only contains two elements (hydrogen and helium) is too small to draw any conclusive trends from it, especially

pos: Period 2 element groups; for example, fluorine is the most reactive halogen, neon is the most inert noble gas, and lithium is the least reactive alkali metal. All period 2 elements completely obey the Madelung rule; in period 2s, lithium and beryllium fill the 2s subshell, and boron, carbon, nitrogen, oxygen, fluorine, and neon fill the 2p subshell. The period shares this trait with periods 1 and 3, none of which contain transition elements or inner transition elements, which often vary from the rule. Lithium (Li) is an alkali metal with atomic number 3, occurring naturally in two isotopes: Li and Li. The

pos: Effective atomic number comparing materials. In many textbooks and scientific publications, the following - simplistic and often dubious - sort of method is employed. One such proposed formula for the effective atomic number, Z, is as follows (Murty 1965): An example is that of water (HO), made up of two hydrogen atoms (Z=1) and one oxygen atom (Z=8), the total number of electrons is 1+1+8 = 10, so the fraction of electrons for the two hydrogens is (2/10) and for the one oxygen is (8/10). So the Z for water is: The effective atomic number is important for predicting how photons interact with

pos: Parity (physics) of formula_59, The overall parity of a many-particle system is the product of the parities of the one-particle states. It is -1 if an odd number of particles are in odd-parity states, and +1 otherwise. Different notations are in use to denote the parity of nuclei, atoms, and molecules. Atomic orbitals have parity (-1), where the exponent ℓ is the azimuthal quantum number. The parity is odd for orbitals p, f, ... with ℓ = 1, 3, ..., and an atomic state has odd parity if an odd number of electrons occupy these orbitals. For example, the ground state of

pos: Electron shell Electron shell In chemistry and atomic physics, an electron shell, or a principal energy level, may be thought of as an orbit followed by electrons around an atom's nucleus. The closest shell to the nucleus is called the " shell" (also called "K shell"), followed by the " shell" (or "L shell"), then the " shell" (or "M shell"), and so on farther and farther from the nucleus. The shells correspond with the principal quantum numbers ("n" = 1, 2, 3, 4 ...) or are labeled alphabetically with letters used in the X-ray notation (K, L, M, …). Each shell

pos: Energy level and atomic physics, an electron shell, or a principal energy level, may be thought of as an orbit followed by electrons around an atom's nucleus. The closest shell to the nucleus is called the " shell" (also called "K shell"), followed by the " shell" (or "L shell"), then the " shell" (or "M shell"), and so on farther and farther from the nucleus. The shells correspond with the principal quantum numbers ("n" = 1, 2, 3, 4 ...) or are labeled alphabetically with letters used in the X-ray notation (K, L, M, …). Each shell can contain only a

pos: Magnetic quantum number Magnetic quantum number In atomic physics, the magnetic quantum number, designated by the letter "m", is the third in a set of four quantum numbers (the principal quantum number, the azimuthal quantum number, the magnetic quantum number, and the spin quantum number) which describe the unique quantum state of an electron. The magnetic quantum number distinguishes the orbitals available within a subshell, and is used to calculate the azimuthal component of the orientation of orbital in space. Electrons in a particular subshell (such as s, p, d, or f) are defined by values of "ℓ" (0, 1, 2, or 3).

pos: Two-electron atom to the two outer valence electrons. Two-electron atom In atomic physics, a two-electron atom or helium-like ion is a quantum mechanical system consisting of one nucleus with a charge of "Ze" and just two electrons. This is the first case of many-electron systems where the Pauli exclusion principle plays a central role. It is an example of a three-body problem. The first few two-electron atoms are: The Schrödinger equation for any two-electron system, such as the neutral Helium atom (He, "Z" = 2), the negative Hydrogen ion (H, "Z" = 1), or the positive Lithium ion (Li, "Z" = 3)

pos: Valence electron The number of electrons in an atom's outermost valence shell governs its bonding behavior. Therefore, elements whose atoms can have the same number of valence electrons are grouped together in the periodic table of the elements. As a general rule, a main group element (except hydrogen or helium) tends to react to form a closed shell, corresponding to the electron configuration sp. This tendency is called the octet rule, because each bonded atom has eight valence electrons including shared electrons. The most reactive kind of metallic element is an alkali metal of group 1 (e.g., sodium or potassium); this is

pos: Ionization the avalanche. Ionization efficiency is the ratio of the number of ions formed to the number of electrons or photons used. The trend in the ionization energy of atoms is often used to demonstrate the periodic behavior of atoms with respect to the atomic number, as summarized by ordering atoms in Mendeleev's table. This is a valuable tool for establishing and understanding the ordering of electrons in atomic orbitals without going into the details of wave functions or the ionization process. An example is presented in figure 1. The periodic abrupt decrease in ionization potential after rare gas atoms, for

pos: Chemical element "nuclide") of the element, expressed in atomic mass units (symbol: u). In general, the mass number of a given nuclide differs in value slightly from its atomic mass, since the mass of each proton and neutron is not exactly 1 u; since the electrons contribute a lesser share to the atomic mass as neutron number exceeds proton number; and (finally) because of the nuclear binding energy. For example, the atomic mass of chlorine-35 to five significant digits is 34.969 u and that of chlorine-37 is 36.966 u. However, the atomic mass in u of each isotope is quite close to

neg: Electron shell principle. However, there are a number of exceptions to the rule; for example palladium (atomic number 46) has no electrons in the fifth shell, unlike other atoms with "lower" atomic number. Some entries in the table are uncertain, when experimental data is unavailable. (For example, the elements past 108 have such short half-lives that their electron configurations have not yet been measured.) Electron shell In chemistry and atomic physics, an electron shell, or a principal energy level, may be thought of as an orbit followed by electrons around an atom's nucleus. The closest shell to the nucleus is called the

neg: Core charge across a row of the periodic table, the outer-shell electrons are pulled more and more strongly towards the nucleus and the atomic radius decreases. This can be used to explain a number of periodic trends such as atomic radius, first ionization energy (IE), electronegativity, and oxidizing. Core charge can also be calculated as 'atomic number' minus 'all electrons except those in the outer shell'. For example, chlorine (element 17), with electron configuration 1s 2s 2p 3s 3p, has 17 protons and 10 inner shell electrons (2 in the first shell, and 8 in the second) so: A core charge is

neg: Electron configuration assigned to each subshell placed as a superscript. For example, hydrogen has one electron in the s-orbital of the first shell, so its configuration is written 1s. Lithium has two electrons in the 1s-subshell and one in the (higher-energy) 2s-subshell, so its configuration is written 1s 2s (pronounced "one-s-two, two-s-one"). Phosphorus (atomic number 15) is as follows: 1s 2s 2p 3s 3p. For atoms with many electrons, this notation can become lengthy and so an abbreviated notation is used. The electron configuration can be visualized as the core electrons, equivalent to the noble gas of the preceding period, and the

neg: Effective atomic number Effective atomic number Effective atomic number has two different meanings: one that is the effective nuclear charge of an atom, and one that calculates the average atomic number for a compound or mixture of materials. Both are abbreviated Z. The effective atomic number Z, (sometimes referred to as the effective nuclear charge) of an atom is the number of protons that an electron in the element effectively 'sees' due to screening by inner-shell electrons. It is a measure of the electrostatic interaction between the negatively charged electrons and positively charged protons in the atom. One can view the electrons in

neg: Atomic radius The way the atomic radius varies with increasing atomic number can be explained by the arrangement of electrons in shells of fixed capacity. The shells are generally filled in order of increasing radius, since the negatively charged electrons are attracted by the positively charged protons in the nucleus. As the atomic number increases along each row of the periodic table, the additional electrons go into the same outermost shell; whose radius gradually contracts, due to the increasing nuclear charge. In a noble gas, the outermost shell is completely filled; therefore, the additional electron of next alkali metal will go into

neg: Periodic table so on). Each shell consists of one or more subshells (named s, p, d, f and g). As atomic number increases, electrons progressively fill these shells and subshells more or less according to the Madelung rule or energy ordering rule, as shown in the diagram. The electron configuration for neon, for example, is 1s 2s 2p. With an atomic number of ten, neon has two electrons in the first shell, and eight electrons in the second shell; there are two electrons in the s subshell and six in the p subshell. In periodic table terms, the first time an electron

neg: Atomic orbital electrically neutral atom increases with the atomic number. The electrons in the outermost shell, or "valence electrons", tend to be responsible for an element's chemical behavior. Elements that contain the same number of valence electrons can be grouped together and display similar chemical properties. For elements with high atomic number , the effects of relativity become more pronounced, and especially so for s electrons, which move at relativistic velocities as they penetrate the screening electrons near the core of high- atoms. This relativistic increase in momentum for high speed electrons causes a corresponding decrease in wavelength and contraction of 6s

neg: Electron configuration shells and subshells despite the advances in understanding of the quantum-mechanical nature of electrons. An electron shell is the set of allowed states that share the same principal quantum number, "n" (the number before the letter in the orbital label), that electrons may occupy. An atom's "n"th electron shell can accommodate 2"n" electrons, "e.g." the first shell can accommodate 2 electrons, the second shell 8 electrons, the third shell 18 electrons and so on. The factor of two arises because the allowed states are doubled due to electron spin—each atomic orbital admits up to two otherwise identical electrons with opposite

neg: Atomic number neutral atom, which is "Z" (the atomic number). The configuration of these electrons follows from the principles of quantum mechanics. The number of electrons in each element's electron shells, particularly the outermost valence shell, is the primary factor in determining its chemical bonding behavior. Hence, it is the atomic number alone that determines the chemical properties of an element; and it is for this reason that an element can be defined as consisting of "any" mixture of atoms with a given atomic number. The quest for new elements is usually described using atomic numbers. As of 2010, all elements with

neg: Bohr model a shell structure, in which each shell corresponds to a Bohr orbit. This model is even more approximate than the model of hydrogen, because it treats the electrons in each shell as non-interacting. But the repulsions of electrons are taken into account somewhat by the phenomenon of screening. The electrons in outer orbits do not only orbit the nucleus, but they also move around the inner electrons, so the effective charge Z that they feel is reduced by the number of the electrons in the inner orbit. For example, the lithium atom has two electrons in the lowest 1s orbit,

neg: Alkali metal the nuclear charge (which is equal to the atomic number) is cancelled by the inner electrons; the number of inner electrons of an alkali metal is always one less than the nuclear charge. Therefore, the only factor which affects the atomic radius of the alkali metals is the number of electron shells. Since this number increases down the group, the atomic radius must also increase down the group. The ionic radii of the alkali metals are much smaller than their atomic radii. This is because the outermost electron of the alkali metals is in a different electron shell than the

neg: Atomic radius they provided important evidence for the development and confirmation of quantum theory. The atomic radii decrease across the Periodic Table because as the atomic number increases, the number of protons increases across the period, but the extra electrons are only added to the same quantum shell. Therefore, the effective nuclear charge towards the outermost electrons increases, drawing the outermost electrons closer. As a result, the electron cloud contracts and the atomic radius decreases. In 1920, shortly after it had become possible to determine the sizes of atoms using X-ray crystallography, it was suggested that all atoms of the same element

neg: Core electron chemical bonding and reactions by screening the positive charge of the atomic nucleus from the valence shell of electrons. In transition metals, the distinction between core and valence electrons is less distinct with electrons in the highest d-shell acting more like valence electrons than core electrons. A more complex explanation of the difference between core and valence electrons can be described with atomic orbital theory. In atoms with a single electron the energy of an orbital is determined exclusively by the principle quantum number n. The n=1 orbital has the lowest possible energy in the atom. For large n, the

neg: Electron shell only one electron in their valence shells (alkali metals) or just missing one electron from having a complete shell (halogens) are the most reactive. However, this terminology is somewhat misleading in the case of transition metals. In these elements, a valence electron can also be in an inner shell. Thus, the electrons that determine how an atom reacts chemically are those that travel farthest from the nucleus, that is, those with the highest energy, and not necessarily in the valence shell. The list below gives the elements arranged by increasing atomic number and shows the number of electrons per shell.

neg: Atomic radius the next outer shell, accounting for the sudden increase in the atomic radius. The increasing nuclear charge is partly counterbalanced by the increasing number of electrons, a phenomenon that is known as shielding; which explains why the size of atoms usually increases down each column. However, there is one notable exception, known as the lanthanide contraction: the 5d block of elements are much smaller than one would expect, due to the shielding caused by the 4f electrons. Essentially, atomic radius decreases across the periods due to an increasing number of protons. Therefore, there is a greater attraction between the protons

neg: Electron shell fine spectroscopic structure of some elements. The multiple electrons with the same principal quantum number ("n") had close orbits that formed a "shell" of positive thickness instead of the infinitely thin circular orbit of Bohr's model. The existence of electron shells was first observed experimentally in Charles Barkla's and Henry Moseley's X-ray absorption studies. Barkla labeled them with the letters K, L, M, N, O, P, and Q. The origin of this terminology was alphabetic. A "J" series was also suspected, though later experiments indicated that the K absorption lines are produced by the innermost electrons. These letters were later

neg: Sodium valence shell, resulting in weak metallic bonding and free electrons, which carry energy. Due to having low atomic mass and large atomic radius, sodium is third-least dense of all elemental metals and is one of only three metals that can float on water, the other two being lithium and potassium. The melting (98 °C) and boiling (883 °C) points of sodium are lower than those of lithium but higher than those of the heavier alkali metals potassium, rubidium, and caesium, following periodic trends down the group. These properties change dramatically at elevated pressures: at 1.5 Mbar, the color changes from

neg: Bohr model integer. But Moseley's law experimentally probes the innermost pair of electrons, and shows that they do see a nuclear charge of approximately Z−1, while the outermost electron in an atom or ion with only one electron in the outermost shell orbits a core with effective charge Z−k where k is the total number of electrons in the inner shells. The shell model was able to qualitatively explain many of the mysterious properties of atoms which became codified in the late 19th century in the periodic table of the elements. One property was the size of atoms, which could be determined

neg: Superatom stabilized by organic ligands. In thiolate-protected gold cluster complexes a simple electron counting rule can be used to determine the total number of electrons () which correspond to a magic number via, where is the number of metal atoms (A) in the core, is the atomic valence, is the number of electron withdrawing ligands, and is the overall charge on the complex. For example the Au(p-MBA) has 58 electrons and corresponds to a closed shell magic number. Superatom A superatom is any cluster of atoms that seem to exhibit some of the properties of elemental atoms. Sodium atoms, when cooled

neg: Photoelectric effect a bound electron has been excited (usually K or L shell electrons at gamma ray energies). The probability of the photoelectric effect occurring is measured by the cross-section of interaction, σ. This has been found to be a function of the atomic number of the target atom and photon energy. A crude approximation, for photon energies above the highest atomic binding energy, is given by: Here "Z" is atomic number and "n" is a number which varies between 4 and 5. (At lower photon energies a characteristic structure with edges appears, K edge, L edges, M edges, etc.) The obvious

neg: Nanoclusters into a vacuum in the presence of an inert gas and produced atomic cluster beams. Heer's team and Brack et al. discovered that certain masses of formed metal nanoclusters were stable and were like magic clusters. The number of atoms or size of the core of these magic clusters corresponds to the closing of atomic shells. Certain thiolated clusters such as Au25(SR)18, Au38(SR)24, Au102(SR)44 and Au144(SR)60 also showed magic number stability. Häkkinen "et al" explained this stability with a theory that a nanocluster is stable if the number of valence electrons corresponds to the shell closure of atomic orbitals as

neg: Bohr model Bohr was not able to help. At that time, he thought that the postulated innermost "K" shell of electrons should have at least four electrons, not the two which would have neatly explained the result. So Moseley published his results without a theoretical explanation. Later, people realized that the effect was caused by charge screening, with an inner shell containing only 2 electrons. In the experiment, one of the innermost electrons in the atom is knocked out, leaving a vacancy in the lowest Bohr orbit, which contains a single remaining electron. This vacancy is then filled by an electron from

neg: Spin quantum number "down") operators. Early attempts to explain the behavior of electrons in atoms focused on solving the Schrödinger wave equation for the hydrogen atom, the simplest possible case, with a single electron bound to the atomic nucleus. This was successful in explaining many features of atomic spectra. The solutions required each possible state of the electron to be described by three "quantum numbers". These were identified as, respectively, the electron "shell" number , the "orbital" number , and the "orbital angular momentum" number . Angular momentum is a so-called "classical" concept measuring the momentum of a mass in circular motion about

neg: Transparency and translucency light wave absorption include: In electronic absorption, the frequency of the incoming light wave is at or near the energy levels of the electrons within the atoms which compose the substance. In this case, the electrons will absorb the energy of the light wave and increase their energy state, often moving outward from the nucleus of the atom into an outer shell or orbital. The atoms that bind together to make the molecules of any particular substance contain a number of electrons (given by the atomic number Z in the periodic chart). Recall that all light waves are electromagnetic in

neg: Periodic trends period). However, atomic radii tend to increase diagonally, since the number of electrons has a larger effect than the sizeable nucleus. For example, lithium (145 picometer) has a smaller atomic radius than magnesium (150 picometer). The atomic radius can be further specified as: The ionization potential is the minimum amount of energy required to remove one electron from each atom in a mole of atoms in the gaseous state. The "first ionization energy" is the energy required to remove the first electron, and generally the "nth ionization energy" is the energy required to remove the atom's "n"th electron, after the

neg: Atomic number Atomic number The atomic number or proton number (symbol "Z") of a chemical element is the number of protons found in the nucleus of an atom. It is identical to the charge number of the nucleus. The atomic number uniquely identifies a chemical element. In an uncharged atom, the atomic number is also equal to the number of electrons. The sum of the atomic number "Z" and the number of neutrons, "N", gives the mass number "A" of an atom. Since protons and neutrons have approximately the same mass (and the mass of the electrons is negligible for many purposes)

neg: Atomic orbital atomic orbitals. The repeating "periodicity" of the blocks of 2, 6, 10, and 14 elements within sections of the periodic table arises naturally from the total number of electrons that occupy a complete set of s, p, d and f atomic orbitals, respectively, although for higher values of the quantum number , particularly when the atom in question bears a positive charge, the energies of certain sub-shells become very similar and so the order in which they are said to be populated by electrons (e.g. Cr = [Ar]4"s"3"d" and Cr = [Ar]3"d") can only be rationalized somewhat arbitrarily. With the

neg: Metastable inner-shell molecular state ab initio calculations based on the atomic model x-ray emissions that involve varying number of L-shell holes. However, the satellite data for larger number of L-shell holes significantly deviated from the calculation results. Based on the MIMS model, the x-ray satellite structures are now understood to result from the interaction between the vibrational state of K-MIMS and the L-shell electron ionization channels. Overall, Younger et al. demonstrated the possibility of forming transient molecular states with closed-shell electrons in ab initio calculations for the first time for frozen or slow moving ion systems that can be approximated with the Born-Oppenheimer approximation.

neg: Electron configuration electrons in a d subshell and fourteen electrons in an f subshell. The numbers of electrons that can occupy each shell and each subshell arise from the equations of quantum mechanics, in particular the Pauli exclusion principle, which states that no two electrons in the same atom can have the same values of the four quantum numbers. Physicists and chemists use a standard notation to indicate the electron configurations of atoms and molecules. For atoms, the notation consists of a sequence of atomic subshell labels (e.g. for phosphorus the sequence 1s, 2s, 2p, 3s, 3p) with the number of electrons

neg: Transition metal groups (4 to 11), with some authors including some elements in groups 3 or 12. The elements in group 3 have an "ns"("n" − 1)"d" configuration. The first transition series is present in the 4th period, and starts after Ca ("Z" = 20) of group-2 with the configuration [Ar]4"s", or scandium (Sc), the first element of group 3 with atomic number "Z" = 21 and configuration [Ar]4"s"3"d", depending on the definition used. As we move from left to right, electrons are added to the same "d"-sub-shell till it is complete. The element of group 11 in the first transition series

neg: Chemistry: A Volatile History number of electrons: 2 in the first shell; 8 in the second shell; 18 in the third shell, and so on, each shell holding an increasing number of electrons. The chemical behaviour of all elements is explained by the number of electrons in their outer shells: to increase the energetic stability of their electron configurations atoms have a tendency to gain or lose electrons in such a way so as to achieve a full outer shell. Sodium, with 11 electrons – one in its outer-most occupied shell, will transfer an electron in the presence of fluorine to its outer-most occupied

neg: Electron microprobe the innermost shells is characteristic of that element, although lines from different elements may overlap. As the innermost shells are involved, the X-ray line energies are generally not affected by chemical effects produced by bonding between elements in compounds except in low atomic number (Z) elements ( B, C, N, O and F for K and Al to Cl for K) where line energies may be shifted as a result of the involvement of the electron shell from which vacancies are filled in chemical bonding. The characteristic X-rays are used for chemical analysis. Specific X-ray wavelengths or energies are selected

neg: Bohr model (see Electron shell and the later discussion of the "Shell Model of the Atom" below). This was established empirically before Bohr presented his model. Bohr extended the model of hydrogen to give an approximate model for heavier atoms. This gave a physical picture that reproduced many known atomic properties for the first time. Heavier atoms have more protons in the nucleus, and more electrons to cancel the charge. Bohr's idea was that each discrete orbit could only hold a certain number of electrons. After that orbit is full, the next level would have to be used. This gives the atom

neg: Core charge the net charge of a nucleus, considering the completed shells of electrons to act as a 'shield.' As a core charge increases, the valence electrons are more strongly attracted to the nucleus, and the atomic radius decreases across the period. Core charge Core charge is the effective nuclear charge experienced by an outer shell electron. In other words, core charge is an expression of the attractive force experienced by the valence electrons to the core of an atom which takes into account the shielding effect of core electrons. Core charge can be calculated by taking the number of protons in

neg: Core electron sequence. See the periodic table below, organized by subshells. For elements with high atomic number Z, relativistic effects can be observed for core shell electrons. The velocities of core shell s electrons reach relativistic momentum which leads to contraction of 6s orbitals relative to 5d orbitals. Physical properties effected by these relativistic effects include lowered melting temperature of mercury and the observed golden colour of gold and caesium due to narrowing of energy gap. Gold appears yellow because it absorbs blue light more than it absorbs other visible wavelengths of light and so reflects back yellow-toned light. A core electron

neg: Atomic nucleus electromagnetic potential well which binds electrons in atoms. Some resemblance to atomic orbital models may be seen in a small atomic nucleus like that of helium-4, in which the two protons and two neutrons separately occupy 1s orbitals analogous to the 1s orbital for the two electrons in the helium atom, and achieve unusual stability for the same reason. Nuclei with 5 nucleons are all extremely unstable and short-lived, yet, helium-3, with 3 nucleons, is very stable even with lack of a closed 1s orbital shell. Another nucleus with 3 nucleons, the triton hydrogen-3 is unstable and will decay into

neg: Auger electron spectroscopy transition probability and formula_24 is the Auger transition probability. Attempts to relate the fluorescence and Auger yields to atomic number have resulted in plots similar to figure 4. A clear transition from electron to photon emission is evident in this chart for increasing atomic number. For heavier elements, x-ray yield becomes greater than Auger yield, indicating an increased difficulty in measuring the Auger peaks for large Z-values. Conversely, AES is sensitive to the lighter elements, and unlike X-ray fluorescence, Auger peaks can be detected for elements as light as lithium ("Z" = 3). Lithium represents the lower limit for AES

neg: Rutherford model number of charges) in the center, with a radius of about 1.2 × 10 meters × [atomic mass number]. Electrons were found to be even smaller. Later, scientists found the expected number of electrons (the same as the atomic number) in an atom by using X-rays. When an X-ray passes through an atom, some of it is scattered, while the rest passes through the atom. Since the X-ray loses its intensity primarily due to scattering at electrons, by noting the rate of decrease in X-ray intensity, the number of electrons contained in an atom can be accurately estimated. See also

neg: Charge number having stripped off all electrons, the charge number is identical with the atomic number "Z", which corresponds to the number of protons in ordinary atomic nuclei. Unlike in chemistry, subatomic particles with electric charges of two elementary charges (e.g. some delta baryons) are indicated with a superscript "++" or "−−". In chemistry, the same charge numbers are usually indicated as superscript "+2" or "−2". In particle physics, the charge number is a (derived) flavor quantum number. For color-charged particles like quarks and hypothetical leptoquarks, the charge number is a multiple of 1/3. Charge number Charge number ("z") refers to a

neg: Metal ions in aqueous solution about the second solvation shell. This technique requires the use of relatively concentrated solutions. X-rays are scatted by electrons, so scattering power increases with atomic number. This makes hydrogen atoms all but invisible to X-ray scattering. Large angle X-ray scattering has been used to characterize the second solvation shell with trivalent ions such as Cr and Rh. The second hydration shell of Cr was found to have molecules at an average distance of . This implies that every molecule in the first hydration shell is hydrogen bonded to two molecules in the second shell. Diffraction by neutrons also give a

neg: Atomic number was seen as containing 118 neutrons rather than 118 nuclear electrons, and its positive charge now was realized to come entirely from a content of 79 protons. After 1932, therefore, an element's atomic number "Z" was also realized to be identical to the proton number of its nuclei. The conventional symbol "Z" possibly comes from the German word (atomic number). However, prior to 1915, the word "Zahl" (simply "number") was used for an element's assigned number in the periodic table. Each element has a specific set of chemical properties as a consequence of the number of electrons present in the

neg: Chemical element their atomic nucleus; so the atomic number of carbon is 6. Carbon atoms may have different numbers of neutrons; atoms of the same element having different numbers of neutrons are known as isotopes of the element. The number of protons in the atomic nucleus also determines its electric charge, which in turn determines the number of electrons of the atom in its non-ionized state. The electrons are placed into atomic orbitals that determine the atom's various chemical properties. The number of neutrons in a nucleus usually has very little effect on an element's chemical properties (except in the case of

neg: Surface-extended X-ray absorption fine structure oscillatory component of the photoabsorption cross section (for K-shell excitation) is obtained: where the atomic scattering factor in a partial wave expansion with partial wave phase-shifts "δ" is given by "P"("x") is the "l"th Legendre polynomial, γ is an attenuation coefficient, exp(−2"σ""k") is a Debye–Waller factor and weight "W" is given in terms of the number of atoms in the "j"th shell and their distance as The above equation for the "χ"("k") forms the basis of a direct, Fourier transform, method of analysis which has been successfully applied to the analysis of the EXAFS data. The number of electrons arriving

neg: Iodine high electron density and atomic number, iodine absorbs X-rays weaker than 33.3 keV due to the photoelectric effect of the innermost electrons. Organoiodine compounds are used with intravenous injection as X-ray radiocontrast agents. This application is often in conjunction with advanced X-ray techniques such as angiography and CT scanning. At present, all water-soluble radiocontrast agents rely on iodine. The production of ethylenediamine dihydroiodide, provided as a nutritional supplement for livestock, consumes a large portion of available iodine. Another significant use is a catalyst for the production of acetic acid by the Monsanto and Cativa processes. In these technologies, which support

neg: Chemistry valence electrons are shared by two atoms: the resulting electrically neutral group of bonded atoms is termed a molecule. Atoms will share valence electrons in such a way as to create a noble gas electron configuration (eight electrons in their outermost shell) for each atom. Atoms that tend to combine in such a way that they each have eight electrons in their valence shell are said to follow the octet rule. However, some elements like hydrogen and lithium need only two electrons in their outermost shell to attain this stable configuration; these atoms are said to follow the "duet rule",

neg: Electron microprobe or used in spot mode to produce excitation of various effects in the sample. Among these effects are: phonon excitation (heat), cathodoluminescence (visible light fluorescence), continuum X-ray radiation (bremsstrahlung), characteristic X-ray radiation, secondary electrons (plasmon production), backscattered electron production, and Auger electron production. When the beam electrons (and scattered electrons from the sample) interact with bound electrons in the innermost electron shells of the atoms of the various elements in the sample, they can scatter the bound electrons from the electron shell producing a vacancy in that shell (ionization of the atom). This vacancy is unstable and must be filled

neg: Lithium Lithium Lithium (from ) is a chemical element with symbol Li and atomic number 3. It is a soft, silvery-white alkali metal. Under standard conditions, it is the lightest metal and the lightest solid element. Like all alkali metals, lithium is highly reactive and flammable, and is stored in mineral oil. When cut, it exhibits a metallic luster, but moist air corrodes it quickly to a dull silvery gray, then black tarnish. It never occurs freely in nature, but only in (usually ionic) compounds, such as pegmatitic minerals which were once the main source of lithium. Due to its solubility

neg: Lone pair Lone pair In chemistry, a lone pair refers to a pair of valence electrons that are not shared with another atom and is sometimes called a non-bonding pair. Lone pairs are found in the outermost electron shell of atoms. They can be identified by using a Lewis structure. Electron pairs are therefore considered lone pairs if two electrons are paired but are not used in chemical bonding. Thus, the number of lone pair electrons plus the number of bonding electrons equals the total number of valence electrons around an atom. Lone pair is a concept used in valence shell electron

neg: Bond valence method are better matched to water than they are to each other. Several factors influence the coordination number of an atom, but the most important of these is its size; larger atoms have larger coordination numbers. The coordination number depends on the surface area of the atom, and so is proportional to r. If V is the charge on the atomic core (which is the same as the valence of the atom when all the electrons in the valence shell are bonding), and N is the corresponding average coordination number, V/N is proportional to the electric field at the surface of

neg: Parity (physics) or even) or u (ungerade or odd). An electronic state is u if and only if it contains an odd number of electrons in u orbitals. For molecules with no centre of symmetry, including all heteronuclear diatomics as well as the majority of polyatomics, inversion is not a symmetry operation and the orbitals and states cannot be described as even or odd. In atomic nuclei, the state of each nucleon (proton or neutron) has even or odd parity, and nucleon configurations can be predicted using the nuclear shell model. As for electrons in atoms, the nucleon state has odd overall

neg: Bond valence method atom uses for bonding. This is equal to the number of electrons in its valence shell if all the valence shell electrons are used for bonding. If they are not, the remainder will form non-bonding electron pairs, usually known as "lone pairs". The "valence of a bond", S, is defined as the number of electron pairs forming the bond. In general this is not an integral number. Since each of the terminal atoms contributes equal numbers of electrons to the bond, the bond valence is also equal to the number of valence electrons that each atom contributes. Further, since within

neg: Lithium aircraft) because of the ability of most types of lithium batteries to fully discharge very rapidly when short-circuited, leading to overheating and possible explosion in a process called thermal runaway. Most consumer lithium batteries have built-in thermal overload protection to prevent this type of incident, or are otherwise designed to limit short-circuit currents. Internal shorts from manufacturing defect or physical damage can lead to spontaneous thermal runaway. Lithium Lithium (from ) is a chemical element with symbol Li and atomic number 3. It is a soft, silvery-white alkali metal. Under standard conditions, it is the lightest metal and the lightest

neg: Effective atomic number an atom as being 'stacked' by energy outside the nucleus; the lowest energy electrons (such as the 1s and 2s electrons) occupy the space closest to the nucleus, and electrons of higher energy are located further from the nucleus. The binding energy of an electron, or the energy needed to remove the electron from the atom, is a function of the electrostatic interaction between the negatively charged electrons and the positively charged nucleus. In Iron, atomic number 26, for instance, the nucleus contains 26 protons. The electrons that are closest to the nucleus will 'see' nearly all of them. However,

neg: Effective atomic number the other side; each electron will feel less than the attractive force of 26 protons because the other electron contributes a repelling force. The 4s electrons in Iron, which are furthest from the nucleus, feel an effective atomic number of only 5.43 because of the 25 electrons in between it and the nucleus screening the charge. Effective atomic numbers are useful not only in understanding why electrons further from the nucleus are so much more weakly bound than those closer to the nucleus, but also because they can tell us when to use simplified methods of calculating other properties and

neg: Effective atomic number electrons further away are screened from the nucleus by other electrons in between, and feel less electrostatic interaction as a result. The 1s electron of Iron (the closest one to the nucleus) sees an effective atomic number (number of protons) of 25. The reason why it is not 26 is because some of the electrons in the atom end up repelling the others, giving a net lower electrostatic interaction with the nucleus. One way of envisioning this effect is to imagine the 1s electron sitting on one side of the 26 protons in the nucleus, with another electron sitting on

neg: Internal conversion produce an internal conversion electron in place of a gamma ray if energy is available from within the nucleus, so an atom may produce an Auger electron in place of an X-ray if an electron is missing from one of the low-lying electron shells. (The first process can even precipitate the second one.) Like IC electrons, Auger electrons have a discrete energy, resulting in a sharp energy peak in the spectrum. The electron capture process also involves an inner shell electron, which in this case is retained in the nucleus (changing the atomic number) and leaving the atom (not the

neg: Internal conversion where the atom is fully ionised. During internal conversion, the atomic number does not change, and thus (as is the case with gamma decay) no transmutation of one element to another takes place. Since an electron is lost from the atom, a hole appears in an electron shell which is subsequently filled by other electrons that descend to that empty, lower energy level, and in the process emit characteristic X-ray(s), Auger electron(s), or both. The atom thus emits high-energy electrons and X-ray photons, none of which originate in that nucleus. The atom supplied the energy needed to eject the electron,

neg: Electron shell can contain only a fixed number of electrons: The first shell can hold up to two electrons, the second shell can hold up to eight (2 + 6) electrons, the third shell can hold up to 18 (2 + 6 + 10) and so on. The general formula is that the "n"th shell can in principle hold up to 2("n") electrons. Since electrons are electrically attracted to the nucleus, an atom's electrons will generally occupy outer shells only if the more inner shells have already been completely filled by other electrons. However, this is not a strict requirement: atoms may

neg: Atomic number of the extra protons presumed present in all heavy nuclei. A helium nucleus was presumed to be composed of four protons plus two "nuclear electrons" (electrons bound inside the nucleus) to cancel two of the charges. At the other end of the periodic table, a nucleus of gold with a mass 197 times that of hydrogen, was thought to contain 118 nuclear electrons in the nucleus to give it a residual charge of + 79, consistent with its atomic number. All consideration of nuclear electrons ended with James Chadwick's discovery of the neutron in 1932. An atom of gold now

neg: Oddo–Harkins rule and deuterium nuclei to form helium and lithium nuclei but was too short for every H ion to be reconstituted into heavier elements. In this case, helium, atomic number 2, remains the even numbered counterpart to hydrogen. Thus, neutral hydrogen - or hydrogen paired with an electron, the only stable lepton - constituted the vast majority of the remaining unannihilated portions of matter following the conclusion of inflation. Another exception to the rule is beryllium, which, even with an even atomic number (4) is more rare than the odd number elements to either side of it (lithium and boron). This

neg: Scanning electron microscope flat surfaces, which results in images with a well-defined, three-dimensional appearance. Using the signal of secondary electrons image resolution less than 0.5 nm is possible. Backscattered electrons (BSE) consist of high-energy electrons originating in the electron beam, that are reflected or back-scattered out of the specimen interaction volume by elastic scattering interactions with specimen atoms. Since heavy elements (high atomic number) backscatter electrons more strongly than light elements (low atomic number), and thus appear brighter in the image, BSEs are used to detect contrast between areas with different chemical compositions. The Everhart-Thornley detector, which is normally positioned to one side

neg: Periodic trends 3 and 6. The periodic trends are based on the Periodic Law which states that if the chemical elements are listed in order of increasing atomic number, many of their properties go through cyclical changes, with elements of similar properties recurring at intervals. For example, after arranging elements in their increasing atomic numbers, many of the physical and chemical properties of Lithium, such as its vigorous reactivity with water, recur in sodium, potassium and cesium. This principle was discovered after number of investigations by scientists in nineteenth-century such as Lothar Meyer and Dmitri Mendeleev. Initially, no theoretical explanation for the

neg: Energy level fixed number of electrons: The first shell can hold up to two electrons, the second shell can hold up to eight (2 + 6) electrons, the third shell can hold up to 18 (2 + 6 + 10) and so on. The general formula is that the "n"th shell can in principle hold up to 2("n") electrons. Since electrons are electrically attracted to the nucleus, an atom's electrons will generally occupy outer shells only if the more inner shells have already been completely filled by other electrons. However, this is not a strict requirement: atoms may have two or even

neg: CHELPG CHELPG CHELPG (CHarges from ELectrostatic Potentials using a Grid-based method) is an atomic charge calculation scheme developed by Breneman and Wiberg, in which atomic charges are fitted to reproduce the molecular electrostatic potential (MESP) at a number of points around the molecule. The charge calculation methods based on fitting of molecular electrostatic potential (MESP) (including CHELPG) are not well-suitable for the treatment of larger systems, where some of the innermost atoms are located far away from the points at which the MESP is computed. In such a situation, variations of the innermost atomic charges will not lead to significant changes

neg: Dorin N. Poenaru was explained. Unlike in fission of heavy nuclei, in this case both the liquid drop model deformation energy and the shell corrections versus the number of delocalized electrons of the light fragment reach a minimum at the well known magic number ne=2. It was suggested to use this type of fission mode in nanotechnology. Since 1964 Poenaru collaborated with scientists from JINR Dubna, CRN Strasbourg, Institut de physique nucleaire d'Orsay, CENBG Bordeaux-Gradignan, Vanderbilt University (Nashville), Advanced Science Research Center of Japan Atomic Energy Research Institute Tokai, Institut fuer Theoretische Physik der J. W. Goethe Universitaet, Frankfurt am Main, GSI Helmholtz

neg: Electron about the next –, the excess electrons remained too energetic to bind with atomic nuclei. What followed is a period known as recombination, when neutral atoms were formed and the expanding universe became transparent to radiation. Roughly one million years after the big bang, the first generation of stars began to form. Within a star, stellar nucleosynthesis results in the production of positrons from the fusion of atomic nuclei. These antimatter particles immediately annihilate with electrons, releasing gamma rays. The net result is a steady reduction in the number of electrons, and a matching increase in the number of neutrons.

neg: Metastable inner-shell molecular state was demonstrated. Thereby, the MIMS model was firmly established and confirmed for any combinations of all elements in the periodic table. Specifically, the extensive analyses of the data that relate to hard x-ray generating collisions have resulted in a universal law (Z–dependency) of the binding energy of the homonucleus MIMS bound by K-shell electrons (K-MIMS). Here Z is the atomic number of the constituent atoms of the K-MIMS. Bae further developed a unified theory to elucidate the Z-dependent behavior of the homonucleus K-MIMS, which behaves much like the helium excimer molecule: He*. The MIMS theory also predicted a 1/Z dependency

neg: Core charge Core charge Core charge is the effective nuclear charge experienced by an outer shell electron. In other words, core charge is an expression of the attractive force experienced by the valence electrons to the core of an atom which takes into account the shielding effect of core electrons. Core charge can be calculated by taking the number of protons in the nucleus minus the number of core electrons, also called inner shell electrons, and is always a positive value. Core charge is a convenient way of explaining trends in the periodic table. Since the core charge increases as you move

neg: Racah seniority number Racah seniority number The Racah seniority number (seniority quantum number) formula_1 was introduced by Giulio Racah for the classification of electrons in an atomic configuration. The "seniority number", in a loosing statement, is quantum number additional to the total angular momentum formula_2 and total spin formula_3, which gives the degree of unpaired particles. A spin-independent interaction formula_4 is assumed with the property where formula_2 is the combined angular momentum, formula_7 magnetic quantum number, formula_8 is electrons' orbital angular momenta, and formula_9 is the dimensionless magnetic moment. The equation above shows there is no interaction unless the two electrons' orbital angular

neg: Atom to the positively charged nucleus by the attraction created from opposite electric charges. If an atom has more or fewer electrons than its atomic number, then it becomes respectively negatively or positively charged as a whole; a charged atom is called an ion. Electrons have been known since the late 19th century, mostly thanks to J.J. Thomson; see history of subatomic physics for details. Protons have a positive charge and a mass 1,836 times that of the electron, at . The number of protons in an atom is called its atomic number. Ernest Rutherford (1919) observed that nitrogen under alpha-particle

neg: Chemical element hydrogen and deuterium). Thus, all carbon isotopes have nearly identical chemical properties because they all have six protons and six electrons, even though carbon atoms may, for example, have 6 or 8 neutrons. That is why the atomic number, rather than mass number or atomic weight, is considered the identifying characteristic of a chemical element. The symbol for atomic number is "Z". Isotopes are atoms of the same element (that is, with the same number of protons in their atomic nucleus), but having "different" numbers of neutrons. Thus, for example, there are three main isotopes of carbon. All carbon atoms

neg: Open shell Open shell In the context of atomic orbitals, an open shell is a valence shell which is not completely filled with electrons or that has not given all of its valence electrons through chemical bonds with other atoms or molecules during a chemical reaction. Atoms generally reach a noble gas configuration in a molecule. The noble gases (He, Ne, Ar, Kr, Xe, Rn) are less reactive and have configurations 1s (He), 1s2s2p (Ne), 1s2s2p3s3p (Ar), etc. For molecules it signifies that there are unpaired electrons. In molecular orbital theory, this leads to molecular orbitals that are singly occupied. In computational

neg: Electronegativity Electronegativity Electronegativity, symbol "χ", is a chemical property that describes the tendency of an atom to attract a shared pair of electrons (or electron density) towards itself. An atom's electronegativity is affected by both its atomic number and the distance at which its valence electrons reside from the charged nucleus. The higher the associated electronegativity number, the more an atom or a substituent group attracts electrons towards itself. On the most basic level, electronegativity is determined by factors like the nuclear charge (the more protons an atom has, the more "pull" it will have on electrons) and the number/location of

neg: Introduction to quantum mechanics direction is arbitrary, conventionally the z-direction is chosen. The fourth quantum number, the [[spin quantum number]] (pertaining to the "orientation" of the electron's spin) is denoted , with values + or −. The chemist [[Linus Pauling]] wrote, by way of example: It is the underlying structure and symmetry of atomic orbitals, and the way that electrons fill them, that leads to the organisation of the [[periodic table]]. The way the atomic orbitals on different atoms combine to form [[molecular orbital]]s determines the structure and strength of chemical bonds between atoms. [[File:Dirac 3.jpg|upright|thumb|right|[[Paul Dirac]] (1902–1984)]] In 1928, [[Paul Dirac]] extended the

neg: Mass number The difference between mass number of an atom and its isotopic mass is known as the mass excess. Mass excess should not be confused with mass defect which is the difference between the mass of an atom and its constituent particles (namely protons, neutrons and electrons). There are two reasons for mass defect/excess: The mass number should also not be confused with the standard atomic weight (also called atomic weight) of an element, which is the ratio of the average atomic mass of the different isotopes of that element (weighted by abundance) to the unified atomic mass unit. The atomic

neg: Aluminium-ion battery power density (fast discharge) and high energy density (hold a lot of charge). But lithium is rare, expensive and toxic. It can also develop dendrites, like splinters, that can short-circuit a battery and lead to a fire. Aluminum also transfers energy more efficiently. Inside a battery, the element — lithium or aluminum — give up some of their electrons, which flow through external wires to power a device. Because of their atomic structure, lithium ions can only provide one electron at a time; aluminum can give three at a time. Aluminum is also more abundant than lithium, lowering material costs.

neg: Oddo–Harkins rule neutrons form the atomic nucleus, which accumulates electrons to form atoms. The number of protons in the nucleus, called atomic number, uniquely identifies a chemical element. The Oddo-Harkins rule argues that elements with odd atomic numbers have one unpaired proton and are more likely to capture another, thus increasing their atomic number. It is possible that in elements with even atomic numbers, Protons are paired, with each member of the pair balancing the spin of the other; even parity thus enhances nucleon stability. This postulate, however, does not apply to the universe's most abundant, and simplest element from the periodic

neg: Double electron capture Double electron capture Double electron capture is a decay mode of atomic nucleus. For a nuclide ("A", "Z") with number of nucleons "A" and atomic number "Z", double electron capture is only possible if the mass of the nuclide of ("A", "Z"−2) is lower. In this mode of decay, two of the orbital electrons are captured by two protons in the nucleus, forming two neutrons. Two neutrinos are emitted in the process. Since the protons are changed to neutrons, the number of neutrons increases by 2, the number of protons "Z" decreases by 2, and the atomic mass number "A"