Question

periodic table unit review
we will take the multiple choice test on thursday

1. please identify the correct number of valence electrons for each of the following groups.

a. group 1a:________ c. group 7a:________
b. group 3a:________ d. group 8a:________

Explanation:

• For group 1A, elements have 1 valence electron.
• For group 3A, elements have 3 valence electrons.
• For group 7A, elements have 7 valence electrons.
• For group 8A (noble gases, except helium), elements have 8 valence electrons. Helium has 2 valence electrons, but as a general rule for the group (excluding the special case of He in some basic valence - electron counting for groups), we consider 8.

Answer:

a. 1
b. 3
c. 7
d. 8