Question

cu₂(co₃)
○ copper (ii) carbonate
○ copper carbonate
○ copper (i) carbonate
○ copper carbon oxide

Explanation:

To name the compound \( \text{Cu}_2(\text{CO}_3) \) (note: the correct formula is \( \text{Cu}_2\text{CO}_3 \) or more accurately, the carbonate with copper(I) is \( \text{Cu}_2\text{CO}_3 \); copper(II) carbonate is \( \text{CuCO}_3 \)). Let's analyze the oxidation state of copper. In \( \text{Cu}_2\text{CO}_3 \), the carbonate ion \( \text{CO}_3^{2-} \) has a charge of -2. Let the oxidation state of Cu be \( x \). Then for \( \text{Cu}_2\text{CO}_3 \), we have \( 2x + (-2) = 0 \), so \( 2x = 2 \), \( x = +1 \). So copper has an oxidation state of +1 (copper(I)). The anion is carbonate (\( \text{CO}_3^{2-} \)). So the name should be copper(I) carbonate. Let's check the options:

• copper (II) carbonate: would have Cu with +2, formula \( \text{CuCO}_3 \), not \( \text{Cu}_2\text{CO}_3 \).
• copper carbonate: ambiguous, but usually refers to copper(II) carbonate (\( \text{CuCO}_3 \)).
• copper (I) carbonate: matches the oxidation state of Cu (+1) and the anion carbonate.
• copper carbon oxide: incorrect naming, the anion is carbonate, not a combination of carbon and oxide.

Answer:

copper (I) carbonate