Isotopes of an Element Differ in the Number Of

Question

Isotopes of an element differ in the number of
A) protons in the nucleus.
B) electrons in the nucleus.
C) neutrons in the nucleus.
D) electron clouds.
E) electrons in energy shells.

Accepted Answer

Isotopes of an element have the same number of protons in the nucleus, but different numbers of neutrons. This gives them the same atomic number but different atomic masses. The number of electrons in the nucleus and electron clouds may also vary, but this is not what defines an isotope.