What is the formula for chromium (II) acetate?
The correct answer and explanation is:
The formula for chromium (II) acetate is Cr(C₂H₃O₂)₂.
Explanation:
Chromium (II) acetate consists of chromium in the +2 oxidation state and acetate ions. The acetate ion (C₂H₃O₂⁻) is a common polyatomic ion, made up of two carbon atoms, three hydrogen atoms, and two oxygen atoms. Each acetate ion carries a negative charge of -1.
To determine the formula of chromium (II) acetate, you must first understand the charges involved. Chromium (II) indicates that chromium has a +2 charge in this compound. The acetate ion, being a monovalent anion, has a charge of -1. To balance the charges, two acetate ions are needed to neutralize the +2 charge of chromium.
Thus, the formula is:
- Cr²⁺ (chromium with a +2 charge)
- Two C₂H₃O₂⁻ (acetate) ions, each with a -1 charge.
This results in the neutral compound Cr(C₂H₃O₂)₂. It is important to note that the number of acetate ions is doubled to balance the charge of chromium in its +2 oxidation state.
In general, the process of writing formulas for ionic compounds involves balancing the total positive and negative charges to ensure the compound is neutral. For chromium (II) acetate, this means having two acetate ions for every chromium ion, giving us the final formula of Cr(C₂H₃O₂)₂.
This is typical for compounds involving transition metals like chromium, which can exist in multiple oxidation states, and for which the number of anions must balance the charge of the metal cation to form a stable compound.