3. Lithium Through Neon   Previous PageNext Page
     The Buildup of the Elements

Lithium (symbol Li) has one electron outside the two-electron "helium core" and three protons in its nucleus, giving an electronic arrangement that can be represented by Li 2,1. In the electronic structure diagrams spanning pages 2 to 5, including the figure above, Li has one electron in the white region that represents the incomplete second shell. The man who invented the idea of electron-pair bonds, University of California chemist G. N. Lewis, represented the outer-shell electrons of atoms as dots around the atomic symbol, as shown at the bottom right of Page 7.


Lithium is a soft, silvery metal that enters into chemical reactions with other substances extremely readily, losing its outer electron in the process.

Beryllium (Be) has two electrons in its second shell, and is symbolized by Be 2,2 or by the Lewis dot structure on page 7. It is a harder and less reactive metal than lithium.

Boron, (B) with three outer electrons (B 2,3), is gray, brittle, and only slightly metallic.

  Page 3 of 23 HomeGlossary