Mechanical models of the hydrogen atom.

Mechanical models of the hydrogen atom. Both models are representations of the hydrogen atom. Bohr proposed that a hydrogen atom consisted of a proton nucleus with a positive charge +e, with an electron circling around it in a circular orbit with charge -e. Because the mass of the nucleus is 1836 times larger than the mass of the electron, it can be said to be at rest. In order to keep the electron stable in its orbit, Bohr assumed that the centripetal force on the electron is the inward electrostatic force between the nucleus and the electron. Also, he made the quantum assumption that electrons can only have certain discrete orbitals with certain angular momentums. The electron is also spinning about its own axis as it orbits around the nucleus. In the hydrogen atom model 'A', the magnetic moment of a spinning electron is about twice that for the electron orbit, which is indicated by the vector arrows. In the hydrogen atom motorized model 'B', the hydrogen atom precesses in a magnetic field. Ref.:Modern College Physics by Harvey White, 6th ed., p. 664-683