Isotopes are different atoms of an element which have the same number of protons, but a different number of neutrons from each other.
- Mass of the isotopes of an element differs as the number of neutrons varies.
- The number or protons in the nucleus of an atom determines what chemical element it is.
- Chemical reactions only involve electrons. The protons and neutrons in the nucleus take no part in chemical reactions.
- All atoms with the same electron arrangement, hence, same proton number, have nearly, if not precisely, identical chemical properties, but with different nuclear and physical properties.
- Every chemical element has one or more isotopes. An atom is first identified and labeled according to the number of protons in the nucleus.