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

NameDate

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

In CO₂, each of the 2 oxygen atoms has oxidation number -2. What is carbon's oxidation number, Ari?
In SO₂, each of the 2 oxygen atoms has oxidation number -2. What is sulfur's oxidation number, Esme?
3.
In 4 Fe + 3 O₂ → 2 Fe₂O₃, what happens to oxygen, Kira?
- 0 to −2: it is reduced
- −2 to 0: it is oxidized
- 0 to +2: it is oxidized
4.
Which two things does iron need around it to rust, Luz?
- Heat and carbon
- Oxygen and water
- Salt and sunlight
5.
In a zinc–copper cell, zinc atoms become Zn²⁺. Which metal is the anode, where oxidation happens, Milo?
- Copper
- Zinc
- Both metals
6.
In a zinc–copper cell, which way do electrons flow through the wire, Noah?
- From copper to zinc
- From the air into the cell
- From zinc to copper
7.
Zinc is oxidized inside an alkaline battery. What happens to the zinc atoms, Pia?
- They gain protons
- They lose electrons
- They gain electrons
8.
Which reaction is a redox reaction, Ren?
- HCl + NaOH → NaCl + H₂O
- Zn + CuSO₄ → ZnSO₄ + Cu
- AgNO₃ + NaCl → AgCl + NaNO₃
9.
Is 2 Mg + O₂ → 2 MgO a redox reaction, Tala?
- Yes: Mg goes from 0 to +2
- No: there are no ions
- No: oxygen is not a metal
10.
Is AgNO₃ + NaCl → AgCl + NaNO₃ a redox reaction, Zee?
- No: no oxidation number changes
- Yes: silver swaps its partner
- Yes: a white solid forms

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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