Earth Materials. John O'Brien
Чтение книги онлайн.

Читать онлайн книгу Earth Materials - John O'Brien страница 32

Название: Earth Materials

Автор: John O'Brien

Издательство: John Wiley & Sons Limited

Жанр: География

Серия:

isbn: 9781119512219

isbn:

СКАЧАТЬ intervening electrons. Elements with relatively low first ionization energies are called electropositive elements because they tend to lose one or more electrons and become positively charged cations. Most elements with high first ionization energies are electronegative elements because they tend to add electrons to their electron clouds and become negatively charged anions. Since opposite charges tend to attract, you can imagine the potential such ions have for combining to produce other Earth materials. The arrangement of elements into vertical columns or groups within the periodic table helps us to comprehend the tendency of specific atoms to lose, gain or share electrons. For example, on the periodic table (see Table 2.3), column 2 (IIA) elements commonly exist as divalent (+2) cations because the first and second ionization energies are fairly similar and much lower than the third and higher ionization energies. This permits two electrons to be removed fairly easily from the electron cloud, but makes the removal of additional electrons much more difficult. Column 13 (IIIA) elements commonly exist as trivalent (+3) cations (see Table 2.3). These elements have somewhat similar first, second and third ionization energies, which are much smaller than the fourth and higher ionization energies. The transfer of electrons is fundamentally important in the understanding of chemical bonds and the development of mineral crystals.

Element Ionization energy
First Second Third Fourth Fifth Sixth Seventh Eighth
H 1312
He 2372 5250
Li 520 7297 11 810
Be 899 1757 14 845 21 000
B 800 2426 3 659 25 020 32 820
C 1086 2352 4 619 6 221 37 820 47 260
N 1402 2855 4 576 7 473 9 452 53 250 64 340
O 1314 3388 5 296 7 467 10 987 13 320 71 320 84 070
F 1680 3375 6 045 8 408 11 020 15 150 17 860 СКАЧАТЬ