Earth Materials. John O'Brien
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Название: Earth Materials

Автор: John O'Brien

Издательство: John Wiley & Sons Limited

Жанр: География

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isbn: 9781119512219

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СКАЧАТЬ Elements with principal quantum levels (shells) or azimuthal quantum s‐ and p‐subshells that are completely filled (that is they contain the maximum number of electrons possible) possess very stable electron configurations. These elements include the noble gas elements such as helium (He), neon (Ne), argon (Ar), and krypton (Kr) which, because of their stable configurations, tend not to react with or bond to other elements. For elements other than helium, the highest quantum level stable configuration is s2, p6, sometimes referred to as the stable octet.

Schematic illustration of the diagonal rule for determining the sequence in which electrons are added to the electron cloud; K-shell electrons violet; L-shell blue; M-shell bluish green; N-shell green; O-shell yellow; P-shell orange and Q-shell red.

      2.2.1 Rows (periods) on the periodic table

Simplified periodic table of the elements showing symbols atomic numbers and mass numbersSchematic illustration of simplified periodic table of the elements showing symbols atomic numbers and mass numbers.
Simplified periodic table of the elements showing symbols and electron configurations Schematic illustration of simplified periodic table of the elements showing symbols atomic numbers and mass numbers. Schematic illustration of the electronic configuration of iron.
Simplified periodic table of the elements electronegativities common and valence states Schematic illustration of simplified periodic table of the elements showing symbols atomic numbers and mass numbers.

      2.2.2 Ionization

      The first ionization energy is the amount of energy required to remove one electron from the electron cloud; the second ionization energy is the amount required to remove a second electron and so forth. Ionization energies are lowest for electrons that are weakly held by the nucleus and higher for electrons that are strongly held by the nucleus or are in stable configurations. Ionization energies decrease down the periodic table because the most weakly held outer electrons are shielded from the positively charged nucleus by a progressively larger number СКАЧАТЬ