Question

boron occurs naturally as two isotopes. what is the difference between these isotopes? they have different numbers of electrons and different charges. they have different numbers of neutrons and different charges. they have different numbers of protons and different mass numbers. they have different numbers of neutrons and different mass numbers.

Explanation:

Isotopes of an element have same number of protons but different numbers of neutrons. Different neutron - numbers lead to different mass numbers (sum of protons and neutrons).

Answer:

They have different numbers of neutrons and different mass numbers.