Acids

Nonmetal hydrides - One or more hydrogen with a +1 oxidation state bound to a nonmetal

e.g.  HF, HCl, HBr, HI, H₂S, HCN, and HSCN



Nonmetal oxides - One or more oxygen with a -2 oxidation state bound to a nonmetal

e.g. CO₂, NO₂, SO₂, and SO₃



Nonmetal hydroxides (Oxyacids) - One or more hydroxide groups with an overall oxidation state of -1 bound to a nonmetal

e.g.  HOCl, HONO₂, O₂S(OH)₂, and OP(OH)₃


or more commonly known as:  HClO, HNO₃, H₂SO₄, and H₃PO₄



       Bases
 

Metal hydrirdes - One or more hydrogen with a +1 oxidation state bound to a metal

e.g.  LiH, NaH, KH, MgH₂, and CaH₂



Metal oxides - One or more oxygen with a -2 oxidation state bound to a metal

e.g.  Li₂O, Na₂O, K₂O, MgO, and CaO



Metal hydroxides - One or more hydroxide groups with an overall oxidation state of -1 bound to a metal

e.g.  LiOH, NaOH, KOH, Ca(OH)₂, and Ba(OH)₂



Metal hydroxides are bases because the difference in the electronegativities of between the metal and the oxygen is relatively large.  The electronegativity of the oxygen is much larger than that of the metal, so the electrons tend to remain with the oxygen atom, resulting in the formation of a positive metal ion and the OH^- ion.

Nonmetal hydroxides, however, are acids because the difference in the electronegativities between the nonmetal and the oxygen is relatively small.  The electronegativities of the oxygen is more or less equal to that of the nonmetal, so the electrons are considered to be shared.  The electrons in the O-H bond remain with the oxygen, resulting in the formation of the H⁺ ion and an oxyanion.

Amphoteric - Compounds that can act as either acids or bases.

e.g.  H₂O, Al₂O₃, and AL(OH)₂

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