Which of the following configuration is correct for iron? | Chemistry | SolveeIt

Question

Which of the following configuration is correct for iron?

$1s^2,2s^2 2p^6,3s^2 3p^6 3d^5$

$1s^2,2s^2 2p^6, 3s^2 3p^6, 4s^2, 3d^5$

$1s^2,2s^2 2p^6, 3s^2 3p^6, 4s^2, 3d^7$

$1s^2,2s^2 2p^6, 3s^2 3p^6 3d^6, 4s^2$

Answer

$1s^2,2s^2 2p^6, 3s^2 3p^6 3d^6, 4s^2$

Explanation

Solution

Firstly the electrons are filled in increasing order of energy and then rearrange the subshells in increasing order as
${26}_Fe = 1s^2, 2s^2 2p^6, 3s^2 3p^6 3d^6, 4s^2$

Chemistry Question on d -and f -Block Elements

Solution