Which of the following names and formulas are NOT paired correctly?

• A. sodium chloride, NaCl
• B. lead(II) nitrite, Pb(NO₂)₂
• C. ammonium sulfate, (NH₄)₂SO₄
• D. copper(II) sulfate pentahydrate, CuSO₄ ▪ 5 H₂O
• E. strontium chloride, SrCl₂
• F. All of the above are paired correctly

Answer: (F)

Verified step by step guidance

1. Step 1: Review the chemical naming conventions for ionic compounds. Ionic compounds are named by stating the cation first followed by the anion. The cation is typically a metal or a positively charged polyatomic ion, and the anion is a non-metal or a negatively charged polyatomic ion.
2. Step 2: Examine the formula for sodium chloride, NaCl. Sodium (Na) is a cation with a +1 charge, and chloride (Cl) is an anion with a -1 charge. The charges balance, making NaCl a correctly paired name and formula.
3. Step 3: Analyze the formula for lead(II) nitrite, Pb(NO2)2. Lead(II) indicates a +2 charge on the lead ion, and nitrite (NO2) is a polyatomic ion with a -1 charge. Two nitrite ions are needed to balance the +2 charge of lead, making Pb(NO2)2 correctly paired.
4. Step 4: Check the formula for ammonium sulfate, (NH4)2SO4. Ammonium (NH4) is a polyatomic ion with a +1 charge, and sulfate (SO4) is a polyatomic ion with a -2 charge. Two ammonium ions are needed to balance the -2 charge of sulfate, making (NH4)2SO4 correctly paired.
5. Step 5: Verify the formula for copper(II) sulfate pentahydrate, CuSO4 ▪ 5 H2O. Copper(II) indicates a +2 charge on the copper ion, and sulfate (SO4) is a polyatomic ion with a -2 charge. The formula CuSO4 is correct for copper(II) sulfate, and the addition of 5 water molecules (pentahydrate) is correctly represented as CuSO4 ▪ 5 H2O.