Question

Which describes isotopes? Check all that apply.

Isotopes have the same atomic mass.

Isotopes have the same atomic number.

Isotopes are always stable.

Isotopes are always radioactive.

Isotopes are stable or radioactive.

Isotopes have different mass numbers.

Answer 1

True:
- Isotopes have the same atomic number. (They are the same element, same number of protons.)
- Isotopes have different mass numbers. (They differ in neutron count.)
- Isotopes are stable or radioactive. (Some isotopes are stable, some are unstable/radioactive.)

False:
- Isotopes have the same atomic mass. (Individual isotopes have different masses; the listed "atomic mass" often refers to the element's average atomic mass.)
- Isotopes are always stable.
- Isotopes are always radioactive.