Ionic bonding

Copper(II)-sulfate-pentahydrate-sample.jpg
Sodium chloride, or table salt, features an ionic bond between a sodium ion Na+ and a chloride ion Cl.

Copper(II)-sulfate-pentahydrate-sample.jpg
Copper sulfate, or CuSO4, features an ionic bond between a copper ion Cu2+ and a sulfate ion SO42−.

Both of these compounds dissolve easily in water.