Question

17. What is the ground state electron configuration of potassium? a. [Ar]3d1 b. [Ar]4s C. 1s 2s 2p 3s 3p 3d d. 1s²2s²2p2d1035

am confused with this question

Answer 1

Potassium has atomic number 19

electrons are filled in sub-shells and orbitals according to aufbau principle

according to which,electrons will be filled first in 1s,then,2s,then 2p then 3s then 3p then 4s then 3d then 4p and so on {4s is filled first than 3d as it has low energy }

maximum electrons which can be filled in s sub-shell is 2, p sub-shell is 6, d sub-shell is 10

now writing electronic configuration of potassium

K(19) = 1s² 2s² 2p⁶ 3s² 3p⁶ 4s¹

but Ar(18) = 1s² 2s² 2p⁶ 3s² 3p⁶

electronic configuration of potassium can be written as [Ar] 4s¹

option b is correct