Adam has 18 protons and 18 neutrons, Adam has 19 protons and 18 neutrons, Atoms has 18 protons and neutrons, and D has 16 protons and 20 neutrons. Which of the following are isotopes of the element?
1) Adam has 18 protons and 18 neutrons
2) Adam has 19 protons and 18 neutrons
3) Atoms has 18 protons and neutrons
4) D has 16 protons and 20 neutrons
