How long does the Proterozoic Eon last for? 541 million years
1,500 million years
1,959 million years
543 million years

a and b because with the other three, they simplify to something else.

because the two particles have an equal charge, the charges will cancel out and give the atom an overall charge of 0. so, if at atom has 35 protons in the nucleus, we could expect it to have 35 electrons orbiting that nucleus.