Give the formula and describe the structure of a noble gas species which is isostructural with : (i) `IC l_(4)^(-)` (ii) `Ibr_(2)^(-)` (iii) `BrO_(3)^(-)`.

Explanation

(i) Structure of `IC l_(4)^(-)`: I in `IC l_(4)^(-)` has four bond pairs and two lone pairs. Therefore, according to VSEPR theory, it should be square planar. `IC l_(4)^(-)` has `(7+4xx7+1)=36` valence electrons. A noble gas species having 36 valence electrons is `XeF_(4)(8+4xx7=36)`.
Therefore, like `IC l_(4)^(-), XeF_(4)` is also square planar.

(ii) Structure of `IB r_(2)^(-) : IB r_(2)^(-)` has two bond pairs and three lone pairs. So, according to VSEPR theory, it should be linear.
Here, `IBr_(2)^(-)` has `(7+2xx7+1)` valence electrons.
A noble gas species having 22 valence electrons is `XeF_(2)(8+2xx7=22)`.
Thus, like `IBr_(2)^(-), XeF_(2)` is alos linear.

(iii) Structure of `BrO_(3)^(-)` : The central atom Br has seven electrons. Four of these electrons from two double bonds with two oxygen atoms while the fifth electron forms a single bond with `O^(-)` ion. The remaining two electrons from one lone pair. Hence, in all, there are three bond pairs and one lone pair around Br atom in `BrO_(3)^(-)`. Therefore, according to VSEPR theory, `BrO_(3)^(-)` should be pyramidal.
Here, `BrO_(3)^(-)` has `26(7+3xx6+1=26)` valence electrons. A noble gas species having 26 valence electrons is `XeO_(3)(8+3xx6=26)`. Thus, like, `BrO_(3)^(-)XeO_(3)` is also pyramidal.