Answer:
The right answerb is E, according to the aufbau principle.
Step-by-step explanation:
The Aufbau principle states that:
Any electron will occupy the lowest available energy level. For instance, let's work on the electronic configuration of Sodium atom Na. It has 11 electrons and they are all filled into the orbitals according to their energies and starting from the lowest as shown here.
1s² 2sb² 2p⁶ 3s¹ It means that the 1s orbital is filled before the 2s is occupied.b