question_answer

Which is not in accordance to aufbau principle?

A)                 

B)

C)                                

D)       

Correct Answer: C

Solution :

Key Idea Aufbau principle states that in the ground state of an atom, the orbital with lower energy is filled up first before the filling of the orbitals with a higher energy commences. Increasing order of energy of various orbitals is \[1s,\text{ }2s,\text{ }2p,\text{ }3s,\text{ }3p,\text{ }4s,\text{ }3d,\text{ }4p,\text{ }5s,...\text{ }etc.\] Therefore, is not obeyed by aufbau principle. Without fully filling of s subshell electrons cannot enter in p subshell in ground state of atom.