JEE Advanced 2017 · Paper 1 · Chemistry Q10

ChemistryInteger+3Question 28 of 54

The sum of the number of lone pairs of electrons on each central atom in the following species is

$\ce{[TeBr6]^{2-}}$ , $\ce{[BrF2]+}$ , $\ce{SNF3}$ , and $\ce{[XeF3]-}$

(Atomic numbers: N = 7, F = 9, S = 16, Br = 35, Te = 52, Xe = 54)

Your answer

Answer and worked solution

Official answer: 6

Count the lone pairs left on each central atom:

Species	Valence electrons	Used in bonds	Lone pairs
$\ce{[TeBr6]^{2-}}$	6 + 2 = 8	6	1
$\ce{[BrF2]+}$	7 − 1 = 6	2	2
$\ce{SNF3}$ (S≡N, 3 S-F)	6	6	0
$\ce{[XeF3]-}$	8 + 1 = 9	3	3

Total: $1+2+0+3=6$ .

Answer: 6

Topics:VSEPR theory Covalent bonding and Lewis structures

JEE Advanced 2017 · Paper 1, Chemistry question 10