## Introductory Chemistry (5th Edition)

a. $CaCl_{2}$ is an ionic solid. b. $CO_{2}$ is a molecular solid. c. Ni is an atomic solid. d. $I_{2}$ is a crystalline molecular solid.
Ionic solids: Solids having formula units as composite units. Atomic solids: These solids have atoms as composite units. Molecular solids: These solids have molecules as composite units. a. $CaCl_{2}$ has two ions, hence it is ionic solid. b. $CO_{2}$ has two different atoms and is a molecular solid. c. Ni is atomic solid. d. $I_{2}$ is covalently bonded, hence it is crystalline molecular solid.