Chapter 11, Problem 9STP

Interpretation Introduction

Interpretation: The expected electron configuration of iron in ground state needs to be determined.

Concept introduction:Valence electrons are the electrons that occupy the outermost shell and core electrons are the electrons occupying the innermost shell.

Answer to Problem 9STP

Electron configuration of iron is ground is $\text{Fe}={\text{[Ar]4s}}^{\text{2}}{\text{3d}}^{\text{6}}$

Explanation of Solution

Atomic number of iron is 26 and the nearest noble gas of iron is Ar with 18 electrons. So, remaining 8 electrons are to be filled.

Therefore, the electron configuration is $\text{[Ar]}4{\text{s}}^{\text{2}}3{\text{d}}^6$ .

Conclusion

  $\text{[Ar]}$ is shorthand for ${\text{1s}}^{\text{2}}{\text{2s}}^{\text{2}}{\text{2p}}^{\text{6}}{\text{3s}}^{\text{2}}{\text{3p}}^{\text{6}}$ .