Neils Bohr (1885 - 1962)

Bohr introduced the Hydrogen model. In the Hydrogen model, electrons orbit the nucleus in different shells. This model is used to describe the energy level of the hydrogen atom.

Bohr fixed Rutherford’s model by reasoning that electrons move in orbits of a specific size and energy. The energy of an electron depends on the size of the orbit.

The energy of the orbit depends on the size of the electron.  The lowest energy is found in the smallest orbit. The highest energy is found fatherest away from the nucleus. 

The Bohr model explains the Rydberg formula for the spectral emission lines for the atomic hydrogen.  

Explained that  when elements are ignited or exposed to electric fields they give off light. He observed that only certain colors of light are produced.

Responsible for the Solar System model. He reasoned that the electrons orbited around  the nucleus like planets orbit the sun. Bohr claimed that the electrons have different energies and as a result are in different energy shells. When an electron absorbs energy it move to a higher shell. When an electron is releasing energy and is returning back to its original shell, the color of light given off depends on the energies of the two orbits, electrons.