Don,

rub a comb through your hair. the comb takes on static electricity. hold the comb close to a small piece of paper on the floor. the paper will jump up to the comb and stick to it.
take a magnet hold it close to a paper clip that is on the floor. the paper clip will jump up to the magnet.
the point is the attractive force of charge is greater than the attractive force of gravity.

additionally if say a proton and an electron come together to form a neutron, gravity is not strong enough to pull them apart unless quantum mechanical tunneling comes into play.

the mass of an object is what interests gravity not charge, but i see your point that the interaction of particles of one charge or another may play a part in the how they relate to gravity if they do infact relate to gravity on th quantum level.

regards tim