Which scientist is credited with first stating that electrons orbit an atomic nucleus

The scientist which was credited with first stating that electrons orbit an atomic nucleus was Niels Henrik David Bohr. He was the proponent of the Bohr model of the atom, wherein he states that energy level of electrons are distinct and that electrons revolve on stable orbits within the atomic nucleus but can actually transfer from one orbit (level) to another. The orbitals are called: s, p, d and f orbitals.

C. which metal is less dense