Question

WHEN 4f LEVEL OF AN ATOM IS COMPLETELY FILLED WITH ELECTRONS
THE NEXT ELECTRON WILL ENTER INTO
O 5s
O 6s
O 5d
O 5p
​

Answer 1

Answer:

it will enter in 5p

Explanation:

according to the aufbau principal

Answer 2

Answer:

The correct answer is Option C : 5d

Explanation:

Aufbau Principle:

In the ground state of an atom or ion, electrons first fill subshells with the lowest possible energy before moving on to subshells with higher energy, according to the aufbau principle, often known as the aufbau rule.

The subshell ordering by this rule : 1s, 2s, 2p, 3s, 3p, 4s, 3d, 4p, 5s, 4d, 5p, 6s, 4f, 5d, 6p, 7s, 5f, 6d, 7p, 8s, 5g, etc.