Atoms bond to become more stable by filling their outer electron shells.

Ionic bonds form when atoms transfer electrons.

Covalent bonds form when atoms share electrons.

Metallic bonds occur between metal atoms sharing electrons freely.

Ionic compounds form crystals with high melting points.

Covalent compounds can be gases, liquids, or solids.

Water has covalent bonds between hydrogen and oxygen.

Salt has ionic bonds between sodium and chloride ions.

Chemical bonds determine many physical properties of substances.

Breaking and forming bonds involve energy changes.