Educator

Hydrogen Atom

• In 1911, Rutherford established that an atom has a positively charged nucleus, which contains most of the mass of the atom. Surrounding the nucleus are light, negatively charged electrons.
• It was observed that the emission spectra of hydrogen atoms consisted of some sharp lines with well defined wavelengths.
• Bohr model: In 1913 Bohr presented a model of the hydrogen atom, in which the electron was assumed to move in a circle about the nucleus. Bohr assumed that only certain orbits were allowed, and that the atom emits or absorbs a photon when the electron makes a transition from one orbit to another. He succeeded in deriving the line spectrum of hydrogen. However, almost nothing else could be explained by this model, and there was no way to extend it to other atoms.
• It took the emergence of quantum mechanics, as developed by Schrodinger, Heisenberg, and others, to set the stage for the new era of modern physics.