Isotopes of an element have the same
- A. number of neutrons but different numbers of protons
- B. number of protons but different numbers of neutrons
- C. mass number but different atomic numbers
- D. number of protons and neutrons
Explanation
Atomic number fixes the element, so isotopes share chemical behaviour but differ in mass, as carbon 12 and carbon 14 do. Different proton numbers would make them different elements entirely. The difference in mass is what allows isotopes to be separated in a mass spectrometer.