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  2. Electronegativity - Wikipedia

    en.wikipedia.org/wiki/Electronegativity

    where ε s,p are the one-electron energies of s- and p-electrons in the free atom and n s,p are the number of s- and p-electrons in the valence shell. It is usual to apply a scaling factor, 1.75×10 −3 for energies expressed in kilojoules per mole or 0.169 for energies measured in electronvolts, to give values that are numerically similar to ...

  3. Atomic number - Wikipedia

    en.wikipedia.org/wiki/Atomic_number

    The atomic number or nuclear charge number (symbol Z) of a chemical element is the charge number of an atomic nucleus. For ordinary nuclei composed of protons and neutrons, this is equal to the proton number (np) or the number of protons found in the nucleus of every atom of that element. The atomic number can be used to uniquely identify ...

  4. Ionization energy - Wikipedia

    en.wikipedia.org/wiki/Ionization_energy

    Ionization energy trends plotted against the atomic number, in units eV.The ionization energy gradually increases from the alkali metals to the noble gases.The maximum ionization energy also decreases from the first to the last row in a given column, due to the increasing distance of the valence electron shell from the nucleus.

  5. Valence (chemistry) - Wikipedia

    en.wikipedia.org/wiki/Valence_(chemistry)

    The valence is the combining capacity of an atom of a given element, determined by the number of hydrogen atoms that it combines with. In methane, carbon has a valence of 4; in ammonia, nitrogen has a valence of 3; in water, oxygen has a valence of 2; and in hydrogen chloride, chlorine has a valence of 1. Chlorine, as it has a valence of one ...

  6. Aufbau principle - Wikipedia

    en.wikipedia.org/wiki/Aufbau_principle

    The maximum number of electrons in a subshell is equal to 2(2 l + 1), where the azimuthal quantum number l is equal to 0, 1, 2, and 3 for s, p, d, and f subshells, so that the maximum numbers of electrons are 2, 6, 10, and 14 respectively. In the ground state, the electronic configuration can be built up by placing electrons in the lowest ...

  7. List of elements by atomic properties - Wikipedia

    en.wikipedia.org/wiki/List_of_elements_by_atomic...

    This is a list of chemical elements and their atomic properties, ordered by Atomic number.. Since valence electrons are not clearly defined for the d-block and f-block elements, there not being a clear point at which further ionisation becomes unprofitable, a purely formal definition as number of electrons in the outermost shell has been used.

  8. Electron affinity - Wikipedia

    en.wikipedia.org/wiki/Electron_affinity

    The electron affinity (Eea) of an atom or molecule is defined as the amount of energy released when an electron attaches to a neutral atom or molecule in the gaseous state to form an anion. X (g) + e − → X − (g) + energy. This differs by sign from the energy change of electron capture ionization. [1] The electron affinity is positive when ...

  9. Electron configurations of the elements (data page) - Wikipedia

    en.wikipedia.org/wiki/Electron_configurations_of...

    Here [Ne] refers to the core electrons which are the same as for the element neon (Ne), the last noble gas before phosphorus in the periodic table. The valence electrons (here 3s 2 3p 3) are written explicitly for all atoms. Electron configurations of elements beyond hassium (element 108) have never been measured; predictions are used below.