Valence Electrons

Cliff Notes

I. Review

A. Draw atoms using shell models

B. When filling up shells, last shell usually isn't full

II. Valence Electrons

A. valence electrons: the e- on the outermost shell of an atom

-Examples: Nitrogen has 5 valence e-

Number of valence e- in Sulfur? Calcium?

B. Electron Dot Diagram: used to show number of valence electrons in periodic table

1. draw dots in one at a time on each side

-Examples: draw electron dot diagrams of Nitrogen, Sulfur, Calcium

C. Elements in the same group have the same number of valence e-

D. Octet rule: elements are stable when their valence shell is full (8 e-)