2.  A covalent bond is formed when two atoms share electrons.  Covalent bonds usually form between two or more nonmetals. CO  A molecule is a neutral group of atoms joined by covalent bonds. Ex. H 2 O

3.  When two atoms share 2 pairs of electrons, it forms a double bond.  When atoms share 3 pairs of electrons, it forms a triple bond.

4.  Atoms of some elements pull more strongly on shared electrons than do other atoms. As a result, the electrons are pulled more toward one atom, causing the bonded atoms to have slight electrical charges.  A covalent bond in which electrons are shared unequally is a polar bond.  A covalent bond in which electrons are shared equally is a nonpolar bond.

5.  Metal atoms form compounds with one another by combining or pooling their valence electrons.  A metallic bond is formed when many metal atoms share their pooled valence electrons.