Explain Aufbau principle with an example .

Explanation

Autbau principle : Orbitals are filled in the order of increasing energy.
Two general rules h elp u s to predict electronic configuration.
1) Electrons are assigned to orbitals in order of increasing value of (n + l)
. 2) For sub-shells with the same value of (n + l ). electrons are assigned first to the sub-shell with lower 'n '.
Ascending order of energies of various atomic orbitals is given below :
`1 s lt 2 s lt 2p lt 3s lt 3p lt 4s lt 3d lt 4 p lt 5s lt 4 d lt 5p lt 6 s lt 4 f lt 5d lt 6p lt 7 s lt 5 f lt 6 d lt 7 p lt 8 s...`