1. F₂: Each fluorine atom has 7 valence electrons. They share one pair of electrons to form a single bond. Each F atom has 3 lone pairs. The Lewis structure shows F-F with 3 lone pairs on each F atom.
2. NO: Nitrogen has 5 valence electrons, oxygen has 6. They form a double bond with one unpaired electron on nitrogen and one lone pair on oxygen. The structure is N=O with a lone pair on O and one unpaired electron on N.
3. O₂: Each oxygen has 6 valence electrons. They form a double bond. Each O has 2 lone pairs. The Lewis structure shows O=O with 2 lone pairs on each O.
4. HCN: Hydrogen has 1 valence electron, carbon has 4, nitrogen has 5. H-C≡N. Carbon forms a single bond with H and a triple bond with N. Nitrogen has one lone pair.
5. H₂S: Hydrogen has 1 valence electron, sulfur has 6. Two H atoms bond to S with single bonds. Sulfur has two lone pairs.
6. CO: Carbon has 4 valence electrons, oxygen has 6. They form a triple bond. Oxygen has one lone pair, carbon has one lone pair.
7. H₃O⁺: Oxygen has 6 valence electrons, each H has 1. Oxygen forms three single bonds with H atoms and has one lone pair. The ion has a +1 charge.
8. O₃: Central O bonded to two O atoms. One single bond, one double bond. Resonance structures. Central O has one lone pair, terminal O with double bond has two lone pairs, terminal O with single bond has three lone pairs. Formal charges: central O +1, double bonded O 0, single bonded O -1.
9. NCl₃: Nitrogen has 5 valence electrons, each Cl has 7. Nitrogen forms three single bonds with Cl atoms. Nitrogen has one lone pair.
10. C₂H₂: Each carbon has 4 valence electrons, each H has 1. C≡C triple bond, each C bonded to one H. Each C has no lone pairs.
11. CH₂Cl₂: Carbon has 4 valence electrons, each H has 1, each Cl has 7. Carbon forms single bonds with two H and two Cl. Carbon has no lone pairs.
12. C₂H₄: Each carbon has 4 valence electrons, each H has 1. C=C double bond, each carbon bonded to two H. No lone pairs.
13. CH₂O: Carbon has 4 valence electrons, each H has 1, oxygen has 6. C=O double bond, carbon bonded to two H. Oxygen has two lone pairs.
14. C₂H₆: Each carbon has 4 valence electrons, each H has 1. C-C single bond, each carbon bonded to three H. No lone pairs.
15. SO₄²⁻: Sulfur has 6 valence electrons, each O has 6. Sulfur forms four single bonds with O atoms. Two O atoms have a -1 charge. Sulfur has no lone pairs. Resonance structures with double bonds.
Parent Tip: Review the logic above to help your child master the concept of lewis dot structure covalent bond worksheet.
