Question

select the correct answer. what is the chemical name of the compound cu(no₃)₂? use the list of polyatomic ions and the periodic table to help you answer.
a. copper nitrate
b. copper nitride
c. copper(ii) nitrate
d. copper(iv) nitrate
e. copper(iv) nitrite

Explanation:

1. First, identify the ions in the compound \( \text{Cu(NO}_3\text{)}_2 \). The polyatomic ion here is \( \text{NO}_3^- \) (nitrate ion), and the metal ion is \( \text{Cu}^{n+} \).
2. To find the charge of \( \text{Cu} \), use the fact that the compound is neutral. Each \( \text{NO}_3^- \) has a charge of -1, and there are 2 of them, so the total negative charge is \( 2\times(-1)= -2 \). For the compound to be neutral, the charge of \( \text{Cu} \) must be +2 (since \( +2 + 2\times(-1)=0 \)).
3. When naming ionic compounds with transition metals (like Cu) that have multiple oxidation states, we use Roman numerals to indicate the charge of the metal. The nitrate ion is \( \text{NO}_3^- \), so the compound is named by stating the metal (copper) with its charge in Roman numerals (II) followed by the name of the polyatomic ion (nitrate).
4. Option A is incorrect because it doesn't indicate the charge of copper (copper can have multiple charges). Option B is incorrect because \( \text{N}^{3 - } \) is nitride, but here we have nitrate (\( \text{NO}_3^- \)). Option D is incorrect because copper has a +2 charge, not +4. Option E is incorrect because the polyatomic ion is nitrate (\( \text{NO}_3^- \)), not nitrite (\( \text{NO}_2^- \)), and copper's charge is +2, not +4.

Answer:

C. copper(II) nitrate