Metals are malleable, meaning they can be bent and shaped. This is because the are made of layers of atoms. The layers can slide over one another when bent, hammered or stretched. Metals can break. Test it: Bend a wire hanger in the same place frequently, and the bond will fatigue and the hanger break.
For a more thorough explanation:
http://matse1.matse.illinois.edu/metals/prin.html
