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  2. Valence electron - Wikipedia

    en.wikipedia.org/wiki/Valence_electron

    The number of valence electrons of an element can be determined by the periodic table group (vertical column) in which the element is categorized. In groups 1–12, the group number matches the number of valence electrons; in groups 13–18, the units digit of the group number matches the number of valence electrons. (Helium is the sole ...

  3. 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 ...

  4. Electron counting - Wikipedia

    en.wikipedia.org/wiki/Electron_counting

    It now has 8 total valence electrons, which obeys the octet rule. CH 4, for the central C; neutral counting: C contributes 4 electrons, each H radical contributes one each: 4 + 4 × 1 = 8 valence electrons ionic counting: C 4− contributes 8 electrons, each proton contributes 0 each: 8 + 4 × 0 = 8 electrons. Similar for H:

  5. 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.

  6. Octet rule - Wikipedia

    en.wikipedia.org/wiki/Octet_rule

    Other rules exist for other elements, such as the duplet rule for hydrogen and helium, and the 18-electron rule for transition metals. The valence electrons can be counted using a Lewis electron dot diagram as shown at the right for carbon dioxide. The electrons shared by the two atoms in a covalent bond are counted twice, once for each atom ...

  7. Hydrogen atom - Wikipedia

    en.wikipedia.org/wiki/Hydrogen_atom

    A hydrogen atom is an atom of the chemical element hydrogen. The electrically neutral hydrogen atom contains a nucleus of a single positively charged proton and a single negatively charged electron bound to the nucleus by the Coulomb force. Atomic hydrogen constitutes about 75% of the baryonic mass of the universe. [1]

  8. Electron configuration - Wikipedia

    en.wikipedia.org/wiki/Electron_configuration

    Neutral atomic hydrogen has one electron in its valence shell, and on formation of water it acquires a share of a second electron coming from oxygen, so that its configuration is similar to that of its nearest noble gas helium (He) with two electrons in its valence shell.

  9. Covalent bond - Wikipedia

    en.wikipedia.org/wiki/Covalent_bond

    Each hydrogen has a valence of one and is surrounded by two electrons (a duet rule) – its own one electron plus one from the carbon. The numbers of electrons correspond to full shells in the quantum theory of the atom; the outer shell of a carbon atom is the n = 2 shell, which can hold eight electrons, whereas the outer (and only) shell of a ...