# How do isotopes differ from ions?

Jul 25, 2014

Isotopes differ in the number of neutrons; in ions the number of electrons is different from the number of protons.

Isotopes are atoms that have the same number of protons but different numbers of neutrons.

Thus, atoms of $\text{_6^12"C}$ and of $\text{_6^13"C}$ are isotopes of each other. They both contain 6 protons, but one contains 6 neutrons and the other contains 7 neutrons.

Ions are atoms that have either gained or lost electrons.

Every atom has the same number of electrons and protons.

If an atom gains an electron, it gets a negative charge. If it loses an electron, it gets a positive charge. All ions have a charge.

If a carbon atom gains an electron, it becomes a C⁻ ion. If it loses an electron, it becomes a C⁺ ion.