What is the charge on the Cr ion in the ionic compound Cr_2O_3?

• A. +1
• B. +3
• C. +6
• D. +2

Answer: (B)

Verified step by step guidance

1. Identify the ions present in the compound Cr_2O_3: chromium (Cr) and oxygen (O).
2. Recall that oxygen typically has a charge of -2 in ionic compounds.
3. Set up an equation to represent the total charge balance in the compound. Since the compound is neutral, the sum of the charges must be zero.
4. Let the charge on each chromium ion be x. There are 2 chromium ions and 3 oxygen ions, so the total charge is: 2x + 3(-2) = 0.
5. Solve the equation for x: 2x - 6 = 0, which leads to x = +3. This means the charge on each chromium ion is +3.