JEE Advanced levelSingle correct optionDifficulty 3 of 3ph156
The total number of Xe-F bond pairs in XeFX7X− and XeFX8X2− together, minus the total number of lone pairs on Xe in the same two ions, is
A11
B13
C15
D17
Answer: B
XeFX7X−: 8+7+1=16 electrons, i.e. 8 pairs, with 7 bond pairs and 1 lone pair. XeFX8X2−: 8+8+2=18 electrons, 9 pairs, with 8 bond pairs and 1 lone pair. Result = (7+8)−(1+1)=13.