Answer
a. 2 electrons gained.
b. 2 electrons lost.
c. 1 electron gained.
d. 1 electron lost.
e. 1 electron lost.
Work Step by Step
1. Determine if each element is a metal or a nonmetal.
a. Nonmetal
b. Metals
c. Nonmetal
d. Metal
e. Metal
2. For the metals, determine how many valence electrons each one has; this is the number of electrons lost when they form ions.
b. All elements from Group 2A have 2 valence electrons.
d. K is from Group 1A: 1 valence electron.
e. Rb is from Group 1A: 1 valence electron.
3. For the nonmetals, determine how many valence electrons each one has; and then find how many they have to gain in order to reach 8 valence electrons, when forming an ion.
a.O is from Group 6A: 6 valence electrons.
8 - 6 = 2 electrons.
c. F is from Group 7A: 7 valence electrons.
8 - 7 = 1 electron.
