What is an isotope? о
an atom that has gained electrons
O
an atom that has lost electrons
O
two or more forms of an atom that contain different numbers of neutrons
O
two or more forms of an atom that contain different numbers of protons

The answer is C:two or more forms of an atom that contain different numbers of neutrons. An isotope is when there are different forms of an atom, in terms of neutrons. Not to be confused with cations or anions, which are atoms with a difference of electrons or protons, making them charged.

Explanation: I took chemistry in 6th grade.