Isotopes of the same element must have the same number of - a protons + neutrons. b neutrons. c electrons. d protons.

Your answer is A ... They have the same number of protons and neutrons, but a different number of electrons. They have the same number of protons and electrons, but a different number of neutrons. Different isotopes of an element have the same atomic number, but different mass numbers ...

D. Protons

Isotopes of the same element share the same amount of protons only. The number of neutrons can be determined depending on the molar mass of the element minus the number of protons. Example: Isotopes of Carbon are Carbon 12 and Carbon 14

Carbon 12 has a molar mass (molecular weight) of 12 minus 6 protons it has will give you 6 neutrons.

Carbon 14 will have (14-6) = 8 neutrons.

The number of electrons will be the same in both elements as long as they remain as neutral elements