TABLE 1
Numbers of bonds and nonbonding pairs for nonmetals obeying the octet rule and having no formal charge.
Group IVA
Group VA: N, P, As
Group VIA: O, S, Se, Te
Group VIIA: F, Cl, Br, I
C, Si Valence electrons: 4
6
7
5
Bonds: 4, 3, 2, 1
Nonbonding pairs: 0, 1, 2, 3
Lewis dot structures of a single atom show the valence electrons of that atom as dots. Generally, only two dots are shown on any one side of the atom. Atoms forming covalent bonds in a molecule share their dots to form a bond—a single bond is formed from one dot (electron) from each atom, and a double bond is formed when two atoms each share two of their dots.
We draw 'Lewis Structures' showing all the valence electrons in a molecule. One can approach drawing Lewis structures as a puzzle—arrange the total number of valence electrons contributed.
1. Determine the number of valence electrons in each of the atoms listed below.
a. C
b. O
c. N
d. F
Draw Lewis dot structures for the following atoms.
a. Si
b. C
c. N
d. As
e. S
f. Br