4.2 Ionic Bonds

Notes

An ion is an atom with a charge because it has gained or lost electrons.

• Metals tend to lose electrons and form positive ions (cations). Nonmetals tend to gain electrons and form negative ions (anions).
• An ionic bond is the attraction between oppositely charged ions after electrons transfer, usually between a metal and a nonmetal.
• Example: Sodium loses 1 electron (becomes $\text{Na}^+$); chlorine gains 1 (becomes $\text{Cl}^-$). They form NaCl.
• Ionic compounds form crystal lattices, have high melting points, and conduct electricity when melted or dissolved in water.