What is the chemical formula for Copper (II) nitrate?
The Correct Answer and Explanation is:
The chemical formula for Copper (II) nitrate is Cu(NO₃)₂.
Explanation:
Copper (II) nitrate is a compound formed by the combination of copper ions (Cu²⁺) and nitrate ions (NO₃⁻). Here’s a step-by-step breakdown of how the formula is derived:
- Copper Ion (Cu²⁺): Copper in its +2 oxidation state is represented by the ion Cu²⁺. This means copper has lost two electrons, resulting in a 2+ charge.
- Nitrate Ion (NO₃⁻): The nitrate ion is a polyatomic ion consisting of one nitrogen atom (N) bonded to three oxygen atoms (O), with an overall charge of 1-. The nitrate ion is commonly represented as NO₃⁻.
- Balancing Charges: In order to form a neutral compound, the total positive charge must balance the total negative charge. Since the copper ion has a +2 charge (Cu²⁺) and each nitrate ion has a -1 charge (NO₃⁻), two nitrate ions are needed to balance the +2 charge from the copper ion.
- Combining the Ions: To balance the charges, two nitrate ions are required for each copper ion. Therefore, the formula for Copper (II) nitrate becomes Cu(NO₃)₂, indicating one copper ion (Cu²⁺) paired with two nitrate ions (NO₃⁻).
Key Points:
- The (II) in Copper (II) nitrate indicates the +2 oxidation state of the copper ion.
- Nitrate, as a polyatomic ion, always retains its -1 charge.
- The formula reflects the need for two nitrate ions to balance the charge of one Cu²⁺ ion.
This is a typical ionic compound where a metal cation (Cu²⁺) pairs with an anion (NO₃⁻) to form a stable neutral compound.
