Question

Write a note about principal quantum number.

Answer 1

• The principal quantum number represents the energy level in which electron revolves around the nucleus and is denoted by the symbol ‘n’. 
• The ‘n’ can have the values 1, 2, 3,… n = 1 represents K shell; n=2 represents L shell and n = 3, 4, 5 represent the M, N, O shells, respectively.
• The maximum number of electrons that can be accommodated in a given shell is 2n² . 
• ‘n’ gives the energy of the electron,

E_n = \(\frac{(-1312.8)Z^2}{n^2}\) KJ mol^-1 and the distance of the electron form the nucleus is by r_n = \(\frac{(-0.529)n^2}{Z}\)A.