Chapter 5, Problem 88A

Interpretation Introduction

Interpretation:

Electron configuration notation which describes an atom in an excited state needs to be identified.

Concept introduction:

When an electron occupies an energy state which is greater than its ground state, it is said to be in an excited state.

Answer to Problem 88A

d. $\left[Ar\right]4s^{2}3d^{8}4p^1$

Explanation of Solution

Given:

1. $\left[Ar\right]4s^{2}3d^{10}4p^2$
2. $\left[Ne\right]3s^{2}3p^5$
3. $\left[Kr\right]5s^{2}4d^1$
4. $\left[Ar\right]4s^{2}3d^{8}4p^1$

Explanations:

An electron can become excited if extra energy will be given to the electrons present in ground state

In case of electron configuration $\left[Ar\right]4s^{2}3d^{8}4p^1$ one electron jumps from $3d$ to $4p$ and this electron configuration do not following Aufbau Principle (the ground state electrons of an atom fill the orbital with lowest energy first and upcoming electrons are filled in the order of increasing their energies.)

Therefore, the electron configuration notation describes an atom in an excited state is $\left[Ar\right]4s^{2}3d^{8}4p^1$.

Conclusion

All other options are incorrect because they are following Aufbau Principle of the ground state electrons configuration of an atom.