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ScienceQuest

Fluorine (F₂) Lewis structure

14 valence electrons, linear

F F
F₂ as the Lewis Structure Generator draws it: lone pairs as dots.

Build F₂ step by step in the Lewis Structure Generator

What is the Lewis structure of F₂?

Fluorine, F₂, has 14 valence electrons. Its two atoms are joined by one F−F single bond. It carries three lone pairs on each F. Every formal charge is zero. As two atoms it is linear, and the molecule is nonpolar.

Valence electrons in F₂

Element Group Valence electrons Atoms Electrons
Fluorine 17 7 2 14
Total 14

In one line: 2 × 7 = 14. Each atom brings the valence electrons its group gives it.

How to draw the F₂ Lewis structure

  1. Count the valence electrons. Valence electrons: each F 7. 2 × 7 = 14.
  2. Join the two atoms. With only two atoms there is no choice to make: they bond to each other.
  3. Join the atoms with single bonds. One single bond uses 2 electrons, leaving 14 − 2 = 12.
  4. Place the lone pairs. Neither atom is an outer one, so the 12 left go on the two atoms as three lone pairs on each F. Now each F has 8 electrons round it.
  5. Make multiple bonds where needed. Each F already has an octet, so no lone pair needs to become a bond.

Lone pairs and formal charges in F₂

Atom Number Bonds Lone pairs Electrons round it Formal charge, V − N − B/2
F 2 one single bond 3 8 7 − 6 − 1 = 0

V is the atom’s valence electrons, N its nonbonding electrons and B its bonding electrons. The formal charges add up to 0, the molecule’s overall charge.

Shape and polarity of F₂

Central atom none, two atoms
Electron geometry linear
Molecular geometry linear
Ideal bond angle none, two atoms
Polarity, an estimate nonpolar

Two identical atoms share the electrons equally.

F₂ Lewis structure compared with its molecular orbital diagram

Lewis structure Molecular orbital diagram
Bond order 1 1
Unpaired electrons 0 0

In the molecular orbital diagram F₂’s 14 valence electrons put 8 in bonding orbitals and 6 in antibonding ones, so its bond order is (8 − 6)/2 = 1. The Lewis structure gives the same bond order and the same number of unpaired electrons. The measured bond length is 141 pm (Huber and Herzberg, Constants of Diatomic Molecules, 1979). The Molecular Orbital Diagram Visualizer draws the diagram level by level.

Work with F₂