Hydrogen Emission Spectrum

On heating small sample of hydrogen gas, its molecule break down into atoms. The electrons in different hydrogen atoms absorb different amount of energy therefore   jump to different higher energy state (Excited state). The time period for excited state is only 10^-6 to 10^-8 second .So electrons come back to their ground state in one or more jumps by emitting radiation (energy) of different wavelengths. Radiations of different wavelength are obtained as lines. .[Collection of these lines (obtain when electron jump to same energy level)  is called series.  All series  are named after the name of their discoverer. These series are collectively called spectrum.]

Fig. Generation of spectral lines in hydrogen spectrum

For example when electron jumps from all the energy level s higher than n=1 i.e. n=2,3, 4, 5,….to n=1  energy level this line fall in ultra violet region  these lines are called Lyman series.

In similar manner, transition from higher energy levels to n=2, n=3,n=4 ,n=5 produce Balmer, Paschen ,Brackett , Pfund Series.  These are summarised below.

Series	from	to	Region
Lyman	n = 2, 3, 4, 5, 6 ………	n = 1	Ultraviolet
Balmer	n =  3, 4, 5, 6,7 ………	n = 2	Visible
Paschen	n =  4, 5, 6,7 ………	n = 3	Near infrared
Brackett	n =  5, 6,7, 8 ………	n = 4	Far infrared
Pfund	n =  6,7,8 ………	n = 5	Far infrared