Quantum numbers

Quantum numbers are used to specify the position of an electron in the space. There are four quantum numbers:
a.Principal quantum number(n): It was proposed by Bohr. Its value ranges from one to infinity. It can never be zero negative or fractional. It determines main energy levels,average distance of nucleusand energy of electron.
b.Azimuthal quantum number(l): It was given by Sommerfield.It represents subshell. It determines orbital angular momentum of electrons,shape of subshell and energy associated with orbital angular momentum of electron. Its value ranges from 0 to (n-1).
c.Magnetic quantum number(m): It was given by Lande. It explains the orientation of orbitals in space. It explains Starks and Zeeman effect.For a given value of l there are (2l+1) values of m ranging from -l to +l.
d.Spin quantum numbers(s): It was given by Goudsmit and Uhlenbeck. It is used to describe spin orientation of electron. Its value is either +1/2 or - 1/2.