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

To determine the number of species with one lone pair on the central atom Xenon, we must analyze the electron arrangement for each compound. Xenon (Xe) is in Group 18, meaning it already has 8 valence electrons. We'll assess each compound to see if one lone pair is present on Xenon.

• XeF₅⁺: Xe contributes 8 valence electrons, and each F contributes 1, totaling 13 electrons. The positive charge removes 1 electron, resulting in 12 electrons (6 pairs). Arranging 5 bonds with F atoms (5 pairs) leaves Xe with 1 lone pair.
• XeO₃: Xe provides 8 electrons, and each O provides 2, totaling 14 electrons. 3 double bonds (6 pairs) leave no lone pairs on Xe.
• XeO₂F₂: Xe offers 8 electrons, each O provides 2, and each F provides 1, for a total of 14 electrons (7 pairs). Using 4 for bonds (2 O and 2 F), 1 pair is left lone on Xe.
• XeF₅^-: Xe has 8 electrons, each F contributes 1, and the negative adds 1, for a total of 14 electrons (7 pairs). 5 pairs form Xe-F bonds, leaving 2 lone pairs.
• XeO₃F₂: Xe supplies 8 electrons, each O provides 2, and each F provides 1, giving 18 electrons (9 pairs). Using 5 pairs for bonding leaves 1 lone pair on Xe.
• XeOF₄: Xe starts with 8 electrons, O with 2, and F with 1 each, totaling 16 electrons (8 pairs). Using 5 pairs for bonds leaves 1 lone pair on Xe.
• XeF₄: Xe contributes 8 electrons, F atoms contribute a total of 4, totaling 12 electrons (6 pairs). 4 pairs form bonds, leaving 2 lone pairs on Xe.

Based on the analysis, the number of species with a single lone pair on Xenon is 4. This count matches the specified range (4,4).