IONIC:

• loss or gain of electrons
• dissolves in water
• crystalline solids
• ionizes in water
• metal bonded to nonmetal
• END is 1.7 or higher
• has electrolytes (conducts electricity)
• high melting/boiling point
• strong bonds, attraction between positive and negative

COVALENT:

• END of 0-1.6
• no electrolytes
• molecular solids, amorphous
• does not ionize
• solubility depends on polarity
• all nonmetals bonded
• sharing of electrons
• low melting/boiling point
• weak bonds due to overlapping valence levels

POLAR:

• not diatomic
• asymmetrical
• has positive and negative sides
• water soluble
• END of 0-.4
• unequal sharing of electrons

NONPOLAR:

• diatomic
• symmetrical
• does not have positive or negative sides
• not water soluble
• END of .5-1.6
• equal sharing of electrons