Chapter 12, Problem 7STP

Interpretation Introduction

Interpretation:

The most stable electronic configuration of bromine ion is to be chosen.

Concept introduction:

The ion which achieve nearest noble gas configuration is most stable.

Answer to Problem 7STP

B

Explanation of Solution

Bromine belongs to 17^th group. So it has tendency to gain one electron and form most stable ion $B{r}^{-}$

Electronic configuration of $Br$ according to Aufbau’s Principle is:

  $\left[Ar\right]4s^{2}3d^{10}4p^5$

Therefore, Electronic configuration of $B{r}^{-}$ :

  $\left[Ar\right]4s^{2}3d^{10}4p^6$

Conclusion

Option A. This is electronic configuration of bromine atom not ion as there are 35 electrons.

Option C. There should be 3d¹⁰ not 4d¹⁰ in the electronic configuration.

Option D. This electronic configuration is wrong as 4d cannot be filled before 3d and 4p. Also, the total number of electrons is 35 which is for bromine atom not ion.