What is the significance of einstein's famous equation e = mc 2 ? (a) energy is not related to mass. (b) mass can be destroyed. (c) energy can be destroyed. (d) mass and energy can convert to one another.

In chemistry, the type of an atom (what element it is) is determined by: a) the number of protons it contains in its nucleus.b) the number of neutrons it contains in its nucleus.c) the number of protons it has in a cloud around the nucleus.d) the number of neutrons it has in a cloud around the nucleus.e) the number of electrons it exchanges with its neighbors.