 A strip of zinc metal is placed in a blue solution of one mower copper II nitrate. The copper plus 2 ion has a greater electron attracting ability than the zinc ion. The copper plus 2 ion gains electrons to produce reddish brown copper that falls to the bottom of the beaker. The colorless zinc plus 2 ions enter the solution. As the concentration of the copper plus 2 ions decreases, the blue color of the solution decreases. In five hours, a large amount of copper metal has collected to the bottom of the beaker and the solution is colorless.