How many electrons does a neutral deuterium atom have?

Question

How many electrons does a neutral deuterium atom have?

Answer 1

Deuterium (²D) is an isotope of hydrogen.  Hydrogen has 1 electron.  Therefore, a neutral deuterium atom has a single electron, just like hydrogen.  It is called deuterium because instead of just a proton for a nucleus, it has a deuteron for a nucleus, which consists of a proton bound to a neutron.  Note that instead of the usual isotope notation that one would expect, i.e. ²H, deuterium is designated as ²D.