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Chemistry — Second Secondary

Chemistry — Second Secondary

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Chemistry — Second Secondary 2026/2027

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Quiz

Question bank: Chapter 3 — The Periodic Table and Classification of Elements

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1.
The oxidation number of manganese in KMnO₄ is
+2
+4
+6
+7
2.
The oxidation number of oxygen in sodium peroxide Na₂O₂ is
−2
−1
0
+1
3.
The oxidation number of hydrogen in CaH₂ is
+1
0
−1
+2
4.
The oxidation number of nitrogen in NH₄+ is
+3
+1
−3
−4
5.
The oxidation number of carbon in CH₃OH is
−4
−2
0
+2
6.
The oxidation number of sulphur in Na₂S₂O₃ is
+2
+4
+6
−2
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