I can see the final section of problems with answers. Let me analyze each one:
15. Cu⁺ and Cl⁻: The answer is CuCl - This is correct. Copper(I) chloride forms a 1:1 ratio.
16. Pb⁴⁺ and O²⁻: The answer is PbO₂ - This is correct. Lead(IV) has +4 charge, oxygen has -2, so we need two oxygen ions to balance (Pb⁴⁺ and 2×O²⁻ = PbO₂).
17. Pb²⁺ and O²⁻: The answer is PbO - This is correct. Lead(II) oxide forms a 1:1 ratio since both ions have charges that cancel out.
18. Mg²⁺ and C⁴⁻: The answer is Mg₂C - This appears to be incorrect. Magnesium has +2 charge, carbon has -4 charge (in carbides), so we would need two magnesium ions (+4 total) to balance one carbon ion (-4). The correct formula should be Mg₂C.
19. Mn⁴⁺ and O²⁻: The answer is MnO₂ - This is correct. Manganese(IV) has +4 charge, oxygen has -2, so we need two oxygen ions to balance (Mn⁴⁺ and 2×O²⁻ = MnO₂).
20. Hg²⁺ and Br⁻: The answer is HgBr₂ - This is correct. Mercury(II) has +2 charge, bromide has -1, so we need two bromide ions.
After reviewing all the problems, I've found that most of the answers are correct. However, there's an error in problem 18 where Mg²⁺ and C⁴⁻ should form Mg₂C, not Mg₂C (which appears to be written correctly but let me double-check the notation).
Actually, looking more carefully at problem 18, the answer written is "Mg₂C" which is correct for magnesium carbide. The formula Mg₂C is indeed the correct formula for magnesium carbide, where magnesium has a +2 charge and carbon has a -4 charge in the carbide ion (C⁴⁻), requiring two magnesium ions to balance one carbon ion.
Therefore, after careful review, all the formulas written on this worksheet appear to be correct.
The solution to this problem is that all the binary formulas written on the worksheet are correct according to standard chemical nomenclature and charge balancing principles. Each compound's formula properly reflects the combination of ions needed to create a neutral compound by balancing the positive and negative charges.
Parent Tip: Review the logic above to help your child master the concept of writing binary formulas worksheet.
