Bohr knew that different gases absorbed and emited unique spectrums of EMR. - From Balmer and Rydberg the hydrogen spectrum could be calculated but "nf" and "ni" had to be whole numbers - To explain why Rutherfords orbiting electrons did not emit EMR Bohr made several postulates Orbiting electrons do not emit EMR Electrons exist in fixed orbits with fixed energy levels EMR is emited only when electrons jump to orbits of lower energy

Bohr determined the size of all orbits in Hydrogen only The size of the orbit is found by taking the orbit number"n" squared (must be a whole number) and multipling it with the value of the first orbit 5.29 x 10^-11 m

Bohr determined the energy of all orbits in Hydrogen only The energy of the orbit is found by taking the inverse of orbit number"n" squared (must be a whole number) and multipling it with the value of the energy of the first orbit -13.6 eV

The Energy of the photons is determined by the energy between energy levels Energy Photon = Energy of the lower state - Energy of the upper state Jumps to lower states give off photons of vastly different energies. Hydrogen as shown below has several jumps that have been given names

- Lyman Series are electron jumps to the first level and yield photons in the Ultraviolet spectrum. - Balmer Series are electron jumps to the Second level and yield photons in the visible spectrum. - Pachen Series are electron jumps to the Third level and yield photons in the infrared spectrum.