Chapter 9, Problem 3STP

Interpretation Introduction

Interpretation:

The electron configuration for iron needs to be determined.

Concept introduction:

Electronic configuration of an element shows the arrangement of electrons in the atomic orbitals. Electron configurations of atoms obey a standard representation in which all electrons sub-shells are arranged in a sequence.

Answer to Problem 3STP

Option A is correct.

Explanation of Solution

Reason for correct option:

In the periodic table iron is located period 4 and group 8. Atomic number of iron is 26 and it is a d-block elements. The electron configuration of iron is as follows:

${\text{1s}}^{\text{2}}{\text{2s}}^{\text{2}}{\text{2p}}^6{\text{3s}}^{\text{2}}{\text{3p}}^{\text{6}}{\text{4s}}^{\text{2}}{\text{3d}}^{\text{6}}=\left[\text{Ar}\right]{\text{4s}}^{\text{2}}{\text{3d}}^{\text{6}}$

Conclusion

Reason for incorrect option:

Option B is the electron configuration of ${\text{Fe}}^{\text{2+}}$ because it has 24 electrons it is formed by losing two electrons.

Option C is incorrect because it does not follow the sequence of the electronic configuration.

Electron configuration given in option D is not correct.