Grade 10 · Science · Chemistry

10th grade Oxidation and reduction: losing and gaining electrons worksheet

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Oxidation and reduction: losing and gaining electrons

Grade 10 Science Worksheet - Challenge Me

NameDate

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

Sulfate, SO₄²⁻, has charge -2, and each of its 4 oxygen atoms is -2. What is sulfur's oxidation number, Ari?
Nitrate, NO₃⁻, has charge -1, and each of its 3 oxygen atoms is -2. What is nitrogen's oxidation number, Bo?
Carbonate, CO₃²⁻, has charge -2, and each of its 3 oxygen atoms is -2. What is carbon's oxidation number, Esme?
4.
In Zn + Cu²⁺ → Zn²⁺ + Cu, which is the reducing agent, Jun?
- Zn²⁺
- Zn
- Cu²⁺
5.
Milo says oxidation can happen only when oxygen takes part. Agree or disagree?
- Disagree: it means losing electrons
- Agree: rusting is what oxidation means
- Agree: the word comes from oxygen
6.
Noah says sodium isn't oxidized in 2 Na + Cl₂ → 2 NaCl because there is no oxygen. Agree or disagree?
- Agree: sodium gains an electron
- Disagree: Na loses an electron
- Agree: oxidation needs oxygen to happen
7.
Pia says a particle that gains electrons is oxidized. Agree or disagree?
- Agree: its oxidation number goes up
- Agree: gaining electrons is oxidation
- Disagree: gaining is reduction
8.
Which half-reaction shows oxidation, Ren?
- Cu²⁺ + 2e⁻ → Cu
- Zn²⁺ + 2e⁻ → Zn
- Zn → Zn²⁺ + 2e⁻
9.
Which half-reaction shows chlorine being reduced, Tala?
- Cl₂ → 2 Cl⁺ + 2e⁻
- Cl₂ + 2e⁻ → 2 Cl⁻
- Cl₂ → 2 Cl⁻ + 2e⁻
10.
In 2 Al + 3 Cu²⁺ → 2 Al³⁺ + 3 Cu, how many electrons move in all, Zee?
- 5
- 3
- 6

Oxidation and reduction: losing and gaining electrons. Every version has 10 questions, and the answer key prints on the second page.

I can say that oxidation is losing electrons and reduction is gaining them, and that they happen together.
I can assign simple oxidation numbers: elements 0, oxygen usually −2, ions their charge, sums to the overall charge.
I can explain rusting and a zinc–copper cell as electron transfer.
I can name the oxidizing and reducing agents and read half-reactions.

Standard: none (TX, FL)

oxidation: Losing electrons; the oxidation number goes up

reduction: Gaining electrons; the oxidation number goes down

oxidation number: A bookkeeping charge given to each atom

oxidizing agent: The substance that takes electrons and is reduced

anode: The electrode where oxidation happens

Your child added the number of atoms and the electrons each loses. Every atom loses that many, so multiply.

Your child kept oxygen's minus sign. The oxidation numbers must add to zero, so the other element takes the opposite sign.

Your child made the oxidation numbers add to zero. In an ion they add to the ion's charge.

What is the most common mistake with oxidation and reduction: losing and gaining electrons?

Your child added the number of atoms and the electrons each loses. Every atom loses that many, so multiply.

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.

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