Draw the Lewis structure for the nitrogen trifluoride (NF
) molecule.
The Correct Answer and Explanation is:
To draw the Lewis structure for nitrogen trifluoride (NF₃):
✅ Correct Lewis Structure:
- Place the nitrogen (N) atom in the center.
- Surround it with three fluorine (F) atoms.
- Form single bonds between N and each F atom.
- Place three lone pairs (6 electrons) on each fluorine atom to complete their octets.
- Place one lone pair (2 electrons) on nitrogen to complete its octet.
Total valence electrons:
- Nitrogen: 5 valence electrons
- Fluorine (3 atoms × 7 e⁻): 21 valence electrons
- Total: 26 valence electrons
Structure Summary:
F
|
F — N — F
..
Each F has 3 lone pairs; N has 1 lone pair.
💡 Explanation
The Lewis structure represents the arrangement of atoms in a molecule along with their valence electrons. For NF₃ (nitrogen trifluoride), nitrogen (N) is the central atom because it is less electronegative than fluorine (F).
Each fluorine atom forms a single covalent bond with nitrogen using one pair of electrons. Since fluorine needs 8 electrons to complete its octet and it shares 2 in the bond, each F requires 6 more electrons as three lone pairs. With 3 fluorine atoms, that’s 3 × 6 = 18 electrons used for lone pairs on fluorine.
Nitrogen forms three single bonds (2 electrons each = 6 electrons). With one lone pair (2 electrons), nitrogen also follows the octet rule, totaling 8 valence electrons.
Counting all electrons:
- 3 bonds = 6 electrons
- 3 lone pairs per F × 3 = 18 electrons
- 1 lone pair on N = 2 electrons
- Total = 6 + 18 + 2 = 26 electrons, matching the available valence electrons.
The geometry of the NF₃ molecule is trigonal pyramidal, similar to ammonia (NH₃), due to the lone pair on nitrogen repelling the bonded pairs. The Lewis structure doesn’t show geometry directly but helps determine bonding and lone pairs, which influence 3D shape.
This structure follows all formal rules: atoms achieve stable electron configurations, and the total number of valence electrons is conserved. Therefore, this is the correct Lewis structure for NF₃.
