Question

please answer it's urgent ​

Answer 1

Answer:

Certain elements have more than one valency. They exhibit variable valency. For example, copper, tin, iron and mercury exhibit variable valency. Copper combines with oxygen to form cuprous oxide (Cu2O) and cupric oxide (CuO).

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Answer 2

Answer:

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Explanation:

1. MERCURY

2. IRON

3. COPPER

4. LEAD