Flexi Says: Neutron - proton ratio (or N/Z ratio or nuclear ratio) can be calculated by dividing the number of neutrons by number of protons for a given atom of an element. Atoms need a certain ratio of neutrons to protons for the nucleus to be stable. Too many or too few neutrons can make it radioactive, which means it is unstable and will decay in order to have a more stable neutron to proton ratio.
