What is the correct formula unit for a compound formed from Pb^{4+} ions and oxide ions (O^{2-})?

• A. Pb_2O_4
• B. PbO_2
• C. Pb_4O
• D. PbO

Answer: (B)

Verified step by step guidance

1. Identify the charges of the ions involved: Pb has a charge of +4 (Pb^{4+}) and oxide has a charge of -2 (O^{2-}).
2. Determine the ratio of ions needed to balance the total positive and negative charges so that the compound is electrically neutral.
3. Set up the charge balance equation: Let the number of Pb^{4+} ions be x and the number of O^{2-} ions be y. The total charge must be zero, so 4x + (-2)y = 0.
4. Solve the equation for the smallest whole number ratio of x to y. For example, 4x = 2y, which simplifies to 2x = y.
5. Write the empirical formula using the ratio found. If x = 1, then y = 2, so the formula is PbO_2.