structure and bonding: energy levels of hydrogen

energy of a hydrogen atom

• energy is directly proportional to -1/quantum number squared

• it is negative because it is an attractive situation

emission spectrum of hydrogen - key concepts

• each line in the spectrum corresponds to an electronic transition between 2 energy levels

• each level has energy E=-R_H/n²

emission spectrum of hydrogen - practical

• pass light through a prism to break it up into individual wavelengths

• the light does not form a continuous spectrum - it forms a series of single wavelengths

• for hydrogen, in visible region there are 4 lines which is given by equation:

1/wavelength = wavenumber = k(1/4-1/n²) where k is a constant and n=3, 4, 5, 6

Balmer series

• experiment which allows us to map out energy levels

• from 6p/5p/4p/3p to 2s where 2s is the lowest energy wavefunction

• 2s and 2p all have same energy for H

• infinite energy is at 0 - this is a proton with an electron that doesn’t know about the proton so there are no waves

general form of equation for all lines in UV and IR regions

1/lamda = wavenumber = R_H(1/m²-1/n²) where m and n are integers

explanation for 4 lines in visible region of hydrogen emission spectrum

• electric discharge on H₂ breaks the bond to give 2 excited state (high energy) H atoms

• High energy H atoms lose energy and become low energy

• As this transition takes place, excess energy is given out as a photon