Question

multiple choice question
for atoms to be different isotopes of an element, they must have different numbers of _.
o electrons
o protons
o neutrons

Explanation:

Isotopes are atoms of the same element. By definition, atoms of the same element have the same number of protons. Electrons can be lost or gained (in ions), but isotopes are neutral atoms (same number of electrons as protons, since overall charge is zero for neutral atoms). The difference between isotopes lies in the number of neutrons. For example, carbon - 12 has 6 neutrons, carbon - 13 has 7 neutrons.

Answer:

neutrons