Deuterium is an isotope of hydrogen, sometimes called heavy hydrogen. Hydrogen (H) has 1 electron, 1 proton, and 0 neutrons when neutral. Deuterium (D) has 1 electron, 1 proton, and 1 neutron when neutral. Because of this, deuterium is heavier in atomic weight than hydrogen. Keeping that in mind, assign the stereochemistry (R or S) to the following chiral carbons. F H CH3 D CD3 NH2