• # question_answer For the energy levels in an atom, which one of the following statements is correct           [AIIMS 1983] A)                 There are seven principal electron energy levels B)                 The second principal energy level can have four sub-energy levels and contains a maximum of eight electrons C)                 The $M$energy level can have maximum of 32 electrons D)                 The $4s$ sub-energy level is at a higher energy than the $3d$ sub-energy level

The second principal shell contains four orbitals viz  $2s,\,2{{p}_{x}},\,\,2{{p}_{y}}$ and $2{{p}_{z}}.$