Give the formula and describe the strncture of a noble gas species which is isostructural with: `IBr_(2)^(-)`

Explanation

Structure of `Ibr_(2)^(-)`: Number of electrons in the valence shell of I = 7 . Number of electrons contributed by each Br- atom `=2xx1=2` . Charge on the central I-atom = 1
`therefore` No. of electrons around the central atom= 7 + 2 + 1 = 10
`therefore` No. of electron-pairs around the central atom=`10/2=5`
Number of bond pairs = 2
[`because`there are two I - Br bonds]
`therefore` Number of lone pairs = 5 - 2 = 3
Thus, in `IBr_(2)^(-)` I has 2 bond pairs and 3 lone pairs. According to VSEPR theory, `IBr_(2)^(-)` should have a linear geometry.
`XeF_(2)` is a noble gas compound having `10(8+1xx2= 10)` electrons in the valence shell of the central atom. It has 2 bond pairs and 3 lone pairs like `IBr_(2)^(-)`. So, `XeF_(2)` has a linear geometry.