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.