1. Types of Bonds Section 2

2. Gain or Loss of Electrons Ion formed Positive Ion = lost a negative electron Negative Ion = gained a negative electron Ion’s charge shows a superscript: K + and I -

3. Ionic Bond 2 ions exchange electrons = ionic bond together Overall has a neutral charge Mg 2+ + Cl - + Cl -  MgCl 2 Usually between metal and nonmetal Usually crystalline solids with high melting points

4. Covalent Bond 2 elements share electrons Single Bond = 1 pair of shared electrons (2 total) H 2 O Double bond = 2 pair of shared electrons (4 total) O2O2 Triple bond = 3 pair of shared electrons (6 total) N2N2 Usually between nonmetals Usually liquids or gases at room temp.

5. Unequal Sharing Strength of bonds relate to size of atoms, charge, and electrons Bigger atoms attract electrons more strongly Become partially negative Other side becomes partially positive This unequal charge makes a “polar” molecule Two like atoms can share electrons evenly making a “nonpolar” molecule.