Question

The number of species from the following carrying a single lone pair on central atom Xenon is ______ .
XeF₅⁺, XeO₃, XeO₂F₂, XeF₅^-, XeO₃F₂, XeOF₄, XeF₄

Hint:

Lone pairs = Valence electrons on Xe −Bonding electrons (shared) − Extra electrons.

Answer 1

Correct Answer: 4

Determining Lone Pairs on Xenon (Xe):

Using VSEPR theory, the number of lone pairs on the central atom Xenon (Xe) is calculated for each species:

1. XeF₅⁺: Xenon has 8 valence electrons. It forms 5 bonds with fluorine, and 1 electron is removed due to the positive charge.
   Lone pairs = 8 − 5 − 1 = 2 (not a single lone pair).
2. XeO₃: Xenon forms 3 bonds with oxygen atoms.
   Lone pairs = 8 − 6 = 2 (not a single lone pair).
3. XeO₂F₂: Xenon forms 4 bonds (2 with oxygen and 2 with fluorine).
   Lone pairs = 8 − 4 = 1 (single lone pair).
4. XeF₅: Xenon forms 5 bonds with fluorine atoms. One extra electron is added due to the negative charge.
   Lone pairs = 8 − 5 + 1 = 2 (not a single lone pair).
5. XeO₃F₂: Xenon forms 5 bonds (3 with oxygen and 2 with fluorine).
   Lone pairs = 8 − 5 = 1 (single lone pair).
6. XeOF₄: Xenon forms 5 bonds (1 with oxygen and 4 with fluorine).
   Lone pairs = 8 − 5 = 1 (single lone pair).
7. XeF₄: Xenon forms 4 bonds with fluorine atoms.
   Lone pairs = 8 − 4 = 2 (not a single lone pair).

Species with a Single Lone Pair:

XeO₂F₂, XeO₃F₂, XeOF₄, XeF₅

Total Number of Such Species:

4