The Bohr model explains that the force of gravity that keeps the planets in orbit is similar to the Coulomb force between the negatively charged electrons and the positively charged protons of the nucleus. The Bohr model compares an atom's electrons with the planets that orbit the Sun.
The Bohr model was proposed by Niels Bohr in 1915 and was built on the Rutherford Model of the atom. Although it is not a completely accurate model, it is useful for describing basic atomic concepts without the need for higher mathematics.
One major problem with the Bohr Model is that it violates the Heisenberg Uncertainty Principle, which states that it is not possible to know both the position and momentum of an electron at the same time.