Isotopes

Isotopes are the atoms of an element with different numbers of neutrons. They have the same proton number, but different nucleon numbers.

Three isotopes of hydrogen

Hydrogen-1: Nucleus: 0 neutron, 1 proton. 1 electron orbiting. Hydrogen-2: Nucleus: 1 neutron, 1 proton. 1 electron orbiting. Hydrogen-3: Nucleus: 1 proton, 2 neutrons. 1 electron orbiting.