This document discusses the hydrogen spectral lines observed in the emission spectrum of hydrogen gas. It explains that hydrogen's emission spectrum shows distinct spectral lines rather than a continuous spectrum, as Bohr's model of the atom accounted for the energy of electronic transitions. The main spectral series observed for hydrogen are the Lyman series in ultraviolet, Balmer series in visible, and Paschen series in infrared regions. The wavelengths of these lines can be described by formulas discovered by Balmer and Rydberg, with Rydberg's formula applying to all hydrogen line series. Spectroscopy is the study of absorption and emission spectra.

1. Hydrogen Spectral Lines
Made by :- Arnav Dabas &
Goransh Chauhan

2. Prism
White light is made
up of all the colors of
the visible spectrum.
Passing it through a
prism separates it.
Author: Thomas V. Green Jr.

3. Line-Emission Spectrum
ground state
excited state
ENERGY IN PHOTON OUT
Courtesy Christy Johannesson www.nisd.net/communicationsarts/pages/chem
656 nm
486 nm
410 nm
434 nm
Wavelength (nm)
Prism
Slits

4. 1. Atomic Spectrum
The emission spectra of
atoms in gaseous
phase do not show a
continous spread of
wavelengths from red to
violet. Such spectra are
called Atomic Spectra.

5. continuous spectrum
absorption spectrum
emission spectrum
hot source
gas
absorption spectrum
emission spectrum

6. Hydrogen Spectral Lines
A B C D E F
Lyman series (UV)
A B C D E
Balmer (Visible)
A B C D
Paschen (IR)
E1
E2
E3
E4
E5
E6
Energy
Bohr’s model of the atom accounted mathematically for the energy of each of the transitions shown.
IR
region
UV
region
656 nm
486 nm
434 nm
410 nm
Davis, Metcalfe, Williams, Castka, Modern Chemistry, 1999, page 97
ionization

7. Balmer shows in 1885,on the
basis of experimental
observations that if spectral
lines are expressed in terms
of wavenumber (v’) ,then the
visible lines of the hydrogen
spectrum obey the formula :

8. Later, a Swedish spectro scopist
named Johannes Rydberg,
noted that all other line series
including Balmer series could
be described by the following
expression :

9. The value 109,677 is known as
Rydberg constant.
The study of absorption or
emission spectra is known as
Spectroscopy.

11. Balmer Series

12. Paschen Series

13. Brackett Series

14. Pfund Series