The total number of lone pairs of electrons in NO₂F is 6.

NO₂F, or nitryl fluoride, features a central nitrogen atom bonded to two oxygen atoms and one fluorine atom, with a total of 24 valence electrons distributed in its Lewis structure. One common resonance form shows one N=O double bond, one N–O single bond, and one N–F single bond, along with specific lone pairs on the surrounding atoms.

Lewis Structure Steps

Calculate total valence electrons: Nitrogen contributes 5, each oxygen 6 (total 12), and fluorine 7, yielding 24 electrons. Place nitrogen centrally due to lower electronegativity, form single bonds first (using 6 electrons), then complete octets on outer atoms—fluorine gets 3 lone pairs (6 electrons), the single-bonded oxygen gets 3 lone pairs (6 electrons), and the double-bonded oxygen gets 2 lone pairs (4 electrons).

Shift electrons for nitrogen’s octet, resulting in formal charges of +1 on N and -1 on single-bonded O, confirming stability. No lone pairs remain on nitrogen.

Lone Pairs Count

Fluorine: 3 lone pairs.
Single-bonded oxygen: 3 lone pairs.
Double-bonded oxygen: 2 lone pairs.
Total: 3 + 3 + 2 = 6 lone pairs.

This holds across resonance structures, as electron distribution varies but total lone pairs stay constant.

The total number of lone pairs of electrons in NO₂F is a key question in molecular chemistry for competitive exams like CSIR NET Life Sciences. Nitryl fluoride (NO₂F) serves as an excellent example to master Lewis structures, valence electrons, and electron pair counting in oxyhalides.

Valence Electrons Calculation

NO₂F contains one nitrogen (group 15, 5 valence e⁻), two oxygens (group 16, 6 each = 12 e⁻), and one fluorine (group 17, 7 e⁻), totaling 24 valence electrons. This count forms the foundation for distributing bonds and lone pairs of electrons in NO₂F.

Drawing NO₂F Lewis Structure

Central N bonds to two O and one F. Initial single bonds use 6 electrons (3 pairs). Assign remaining 18 electrons: F takes 6 (3 lone pairs), each O starts with 6 (3 lone pairs each). Nitrogen lacks octet, so convert one O lone pair to N=O double bond.

Final distribution: N=O (double bond, O with 2 lone pairs), N–O (single, O with 3 lone pairs), N–F (single, F with 3 lone pairs).

Counting Lone Pairs in NO₂F

• Fluorine: 3 lone pairs (6 electrons).

• Single-bonded O: 3 lone pairs (6 electrons).

• Double-bonded O: 2 lone pairs (4 electrons).

Total number of lone pairs of electrons in NO₂F: 6 (12 electrons).

Formal Charges Verification

Formal charge = valence e⁻ – (bonding e⁻/2) – non-bonding e⁻.

• N: 5 – 4 – 0 = +1

• Double-bonded O: 6 – 4 – 4 = 0

• Single-bonded O: 6 – 1 – 6 = -1

• F: 7 – 1 – 6 = 0

Charges balance, confirming the structure.

Exam Tips for NO₂F Lone Pairs

Resonance interchanges single/double bonds between oxygens, but total lone pairs remain 6—practice for quick counting in CSIR NET questions on VSEPR or hybridization. Avoid errors by always totaling outer atom lone pairs post-octet completion.