It has 99 electrons because an element has the same number of protons and electrons
D is the best answer. In many physics problems we treat an extended object as if it were a point with the same mass located at the center of mass.
Pair production<span> is a direct conversion of radiant energy to matter. It is one of the principal ways in which high-energy gamma rays are absorbed in matter. </span>
An atom<span> with a neutral </span>charge<span> is one where the number of electrons is equal to the </span>atomic<span> number
hope i helped</span>
