What characteristic of an element determines its specific isotope?

Answer 1

The number of neutrons in an atom determines the type of isotope.

Answer 2

The answer is Neutrons

Isotopes are different weights of the same element. Remember that an element is what it is based on the number of protons. If you change the number of protons in an element, it becomes a different element. Since isotopes are variants in weight on the SAME element, this can't be the answer.

So what affects weight besides protons? Electrons are so much smaller than protons and neutrons, that differences in their numbers don't significantly affect the weight of the element as a whole, so this can't account for the drastic weight changes among the different isotopes of an element.

So that leaves us with Neutrons. Neutrons weigh about the same as protons, so if you add or take away the number of neutrons in an element, the weight can change dramatically (as we see in many isotopes).

Hope this helps!

Answer 3

The number of neutrons in the nucleus determines the specific isotope of an element. The only difference between isotopes of an element is the number of neutrons present.