Two nuclides having same number of neutrons but differ in protons number:

Isotone - Have the very same neutron number, but different proton number. Isotope - Two forms of same element containing equal numbers of protons but different numbers of neutrons in their nuclei, like a radioactive form of an element. Isobar - Isobars are atoms of different chemical elements that have the same number of nucleons. They have same mass number (Sum of protons plus neutrons). Isomers - Each of two or more compounds with the same formula but a different arrangement of atoms in the molecule and different propeies