Answer
a. 1 electron lost.
b. 3 electrons gained.
c. 1 electron gained.
d. 1 electron lost.
e. 1 electron gained.
Work Step by Step
1. Determine if each element is a metal or a nonmetal.
a. Metal
b. Nonmetal
c. Nonmetal
d. Metal
e. Nonmetal
2. For the metals, determine how many valence electrons each one has; this is the number of electrons lost when they form ions.
a. Li is from Group 1A: 1 valence electron.
d. Na 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.
b. P is from Group 5A: 5 valence electrons.
8 - 5 = 3 electrons.
c. All elements from Group 7A have 7 valence electrons.
8 - 7 = 1 electron.
e. Br is from Group 7A: 7 valence electrons.
8 - 7 = 1 electron.
