QUANTUM NUMBER

Quantum numbers are mathematical expression of any particular electron in an atom.

     In atoms electrons are well arranged in different orbits, sub-orbits and orbitals. In an orbital two electrons have their specific identity to address in its shell position and direction of spin are to be express. All they are denoted using specific mathematical number called the quantum numbers.

Quantum number of four types:-

i) principle quantum number(n)

     The idea of principle quantum number came from Bohr's suggestion of different energy levels, it indicates the shell position of an electron i;e, expression for  the energy of electron for the different shells

Values are

K shell(1st shell) - n=1

L shell(2nd shell) - n=2

M shell(3rd shell) -n=3

N shell(4th shell) - n=4

ii) Angular momentum quantum number(l)

     The idea of angular momentum quantum number came from  Sommerfeld's suggestion, which explain how electron having same energy may have different angular momentum. Its express the sub-shell position of the electron and gives an idea of the angular momentum value of the electron.

For the different sub-shell its value are:-

S sub-shell - 0

P sub-shell - 1

D sub-shell - 2

F sub-shell - 3

iii)Magnetic quantum number(m)

  The idea of magnetic quantum number causes from Zeeman and

stark's observation of different spectral line is applied electromagnetic field.

Magnetic quantum express the orbital position of the electron.

For the different orbitals its values are

For the orbitals of the

iv) Spin quantum number(s)

     The idea of spin quantum number came from the works of  Wolfgang Pauli.

     It express the direction of spin of the electron in the orbital. For clockwise spin the value is +1/2 and for anticlockwise spin the value is -1/2.