If aufbau principle had not been followed then potassium and Calcium would be placed in which block??

Question

Chemistry class 12 chapter#3

Answer 1

Electronic configuration of Ca is 1s² 2s² 2p⁶ 3s² 3p⁶ 4s² 

Filling of 3d orbital starts after the filling of 4s orbitals. If the aufbau principle had not been followed, the filling of 3d orbital would have been prior to filling of 4s orbital and the electronic configuration of Ca would have been  1s² 2s² 2p⁶ 3s² 3p⁶ 3d² and it belongs to d block.