Question

Deuterium on a periodic table?

Answer 1

Deuterium itself is not on the periodic table, but it is known as a heavy hydrogen which is on the table. The nucleus of deuterium is called deuteron and has a neutron in it while most commonly protium has no neutrons in its nucleus. Deuterium is one of two different stable isotopes of hydrogen. I'm not entirely sure on what answer you needed, but I hope this helped:)

Answer 2

Deuterium is not on the periodic table.

Deuterium is simply Hydrogen with one extra neutron (i.e., 1 proton, but the same atomic weight as He).

Its natural abundance factored into the average atomic weight of H which as you notice is NOT exactly 1 amu.