JEE Advanced 2017 Paper 1

Number of electrons around central atom (N) =

V+M±C

2

[V=Valence electrons of central atom,M=+1 for every monovalent atom,-1 for every trivalent atom,C=cationic or anionic charge]
[TeBr6]2−:N=

6+6+2

2

=7
Number of bp = 6
Number of lp = 1
[BrF2]+:N=

7+2−1

2

=4
Number of bp = 2
Number of lp = 2
$SNF_3:N={6-1+3}/2=4$
Number of bp = 4
Number of lp = 0
[XeF3]−:N=

8+3+1

2

=6
Number of bp = 3
Number of lp = 3
The sum of the number of lone pairs of electrons on each central atom = 1 + 2 + 0 + 3 = 6