Question

Which of the following is a reasonable ground-state electron configuration?

a. 1s2 1p6 2s2 2p6 3s2

b. 1s2 2s2 2p6 3s2 3p6 4s2 4d8

c. 1s2 2s2 2p6 3p6

d. 1s1 2s2 2p6 3s1

Answer 1

The reasonable ground-state electron configuration is: 1s2 2s2 2p6 3s2 3p6 4s2 4d8

Answer 2

b) 1s2 2s2 2p6 3s2 3p6 4s2 4d8

Step-by-step explanation:

Electron configuration of an atom is given based on the Aufbau principle which states that electrons are arranged in orbitals such that the lower energy orbitals are filled first. The increasing energy order of orbitals is:

1s < 2s < 2p < 3s < 3p < 4s < 3d < 4p....

s, p ,d orbitals can accommodate a maximum of 2,6 and 8 electrons respectively.

Based on the above ordering, the most reasonable ground state configuration would be:

1s2 2s2 2p6 3s2 3p6 4s2 4d8