What is the total number of lone pairs in IF₅ molecule?

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DSSSB PGT Chemistry (Female) Official Paper (Held On: 06 Jul, 2018 Shift 1)

Answer 1

CONCEPT:

Lone Pairs in a Molecule

Lone pairs are non-bonding pairs of electrons that remain localized on an atom in a molecule.
To determine the number of lone pairs, we use the molecule's Lewis structure and valence electron count.
Lone pairs on the central atom can be calculated by considering the total number of valence electrons and subtracting the bonding electrons used in forming the structure.

EXPLANATION:

IF₅ is an interhalogen compound where iodine (I) is the central atom surrounded by five fluorine (F) atoms.
Steps to determine lone pairs on iodine:
- Iodine belongs to Group 17 and has 7 valence electrons.
- Each fluorine atom forms one single bond with iodine, using 1 electron from iodine for each bond.
- Since there are 5 fluorine atoms, iodine uses 5 of its 7 valence electrons for bonding.
- The remaining 2 electrons on iodine form one lone pair.
The molecular geometry of IF₅ is square pyramidal (based on VSEPR theory), and the lone pair resides on the central iodine atom.

Therefore, the total number of lone pairs in the IF₅ molecule is 1.