Grade 10 · Science · Chemistry

10th grade Draw Lewis structures of molecules worksheet

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Draw Lewis structures of molecules

Grade 10 Science Worksheet - Challenge Me

NameDate

Circle the best answer, or write your answer on the line.

Water has 8 valence electrons and 2 bonding pairs. How many lone pairs are in 3 water molecules, Ari?
Carbon dioxide has 16 valence electrons and 4 bonding pairs. How many lone pairs are in 3 CO₂ molecules, Bo?
Oxygen gas, O₂, has 12 valence electrons and 2 bonding pairs. How many lone pairs are in 5 O₂ molecules, Esme?
4.
A drawing shows a hydrogen with two bonds. What is wrong, Jun?
- Hydrogen needs eight electrons too
- Hydrogen forms one bond
- Nothing is wrong
5.
A drawing of H₂O shows 10 electrons. What is wrong, Luz?
- Oxygen needs 10
- Water has only 8 valence electrons
- It needs 12 electrons for the oxygen
6.
Milo says water's oxygen has only 4 electrons because it has two bonds. Agree or disagree?
- Agree: just the bonding pairs count
- Agree: two bonds is four
- Disagree: its lone pairs count too
7.
Noah says nitrogen in NH₃ breaks the octet rule with only 3 bonds. Agree or disagree?
- Disagree: its lone pair makes 8
- Agree: nitrogen needs 5 bonds to be full
- Agree: 3 bonds make 6
8.
Pia draws O₂ with a single bond. Agree or disagree that this works?
- Agree: oxygen has just 2 electrons to share
- Agree: one bond is enough
- Disagree: it needs a double bond
9.
How is a double bond made when drawing a Lewis structure, Tala?
- A new atom is added
- Electrons are removed
- A lone pair becomes a shared pair
10.
Why does H₂O need no double bonds, Zee?
- Single bonds already complete it
- Oxygen has no lone pairs
- Hydrogen forms two bonds

Draw Lewis structures of molecules. Every version has 10 questions, and the answer key prints on the second page.

I can count a molecule's valence electrons and draw its skeleton with single bonds.
I can place lone pairs so each atom has an octet (hydrogen has 2).
I can use double bonds when single bonds leave atoms short, as in O₂ and CO₂.
I can check a drawing for wrong electron counts or too many bonds.

Standard: none (TX, FL)

Lewis structure: A drawing of a molecule's bonds and lone pairs

lone pair: Two valence electrons not shared in a bond

single bond: One shared pair of electrons

double bond: Two shared pairs of electrons

octet rule: Atoms tend to end with 8 outer electrons

Your child counted each kind of atom once. Add the valence electrons of every atom in the molecule.

Your child took one electron per bond. Each single bond is a shared pair: 2 electrons.

Your child counted lone electrons, not pairs. Divide the leftover electrons by 2 to get lone pairs.

What is the most common mistake with draw lewis structures of molecules?

Your child counted each kind of atom once. Add the valence electrons of every atom in the molecule.

Are these 10th grade science worksheets free to print?

Yes. All 6 printable versions at each level are free to print, with the answer key, and no account is needed.

Every sheet you scan goes into your child’s record: dated, marked and ready for the year-end portfolio. Homeschool records