Can two isotopes of the same element have different numbers of protons?

Hey there!

Your answer is no.

The difference between isotopes is the number of neutrons, not the number of protons.

For example, we have carbon-12 and carbon-14, two different isotopes of carbon. One has 6 protons and 6 neutrons, while one has 6 protons and 8 neutrons. They have the same amount of protons.

If you change the number of protons, then you have a different element. Isotopes are the same element.

Hope this helps!

the answer is c. nacl