1. How many valence electrons are in an atom of phosphorus? (atomic number 15)
a. 2
b. 3
c. 4
d. 5
2. How many electrons does barium have to give up to achive a noble-gas electron configuration?
a. 1
b. 2
c. 3
d. 4
3. Which of the following elements does NOT form an ion with a charge of 1+?
a. fluroine
b. hygrogen
c. potassium
d. sodium
