Question

Isotopes are atoms of the same element that have different _?

Answer 1

Answer:

Neutrons

Explanation:

Isotopes are atoms with same protons and different neutron number.  For eg: Hydrogen has 0 neutrons. But a stable isotope of hydrogen called Deuterium has 1 neutron but both still have 1 proton which makes them isotopes.

Answer 2

Isotopes have different mass number but same atomic number