General Chemistry: Common Polyatomic Ions

Overview

• Memorization of common polyatomic ions is essential in general chemistry.
• Focus on both cations and anions.

Cations

• NH₄⁺: Ammonium ion

Common Anions

• CH₃COO⁻: Acetate ion
• CN⁻: Cyanide ion
• OH⁻: Hydroxide ion
• MnO₄⁻: Permanganate ion

Nitrogen-Oxygen Anions

• NO₃⁻: Nitrate ("ate" = more oxygens)
• NO₂⁻: Nitrite ("ite" = fewer oxygens)

Chlorine-Oxygen Anions

• ClO₃⁻: Chlorate
• ClO₂⁻: Chlorite
• ClO₄⁻: Perchlorate ("per" = +1 oxygen)
• ClO⁻: Hypochlorite ("hypo" = -1 oxygen)

Bromine-Oxygen Anions (Examples)

• BrO₃⁻: Bromate
• BrO⁻: Hypobromite

Sulfur-Oxygen Anions

• SO₄²⁻: Sulfate
• SO₃²⁻: Sulfite
  • HSO₄⁻: Hydrogen Sulfate (aka Bisulfate)
  • HSO₃⁻: Hydrogen Sulfite (similar process)

Carbonate and Phosphate

• CO₃²⁻: Carbonate
  • HCO₃⁻: Hydrogen Carbonate (aka Bicarbonate)
• PO₄³⁻: Phosphate
  • HPO₄²⁻: Hydrogen Phosphate
  • H₂PO₄⁻: Dihydrogen Phosphate

Chromium and Oxalate Ions

• CrO₄²⁻: Chromate
• Cr₂O₇²⁻: Dichromate
• C₂O₄²⁻: Oxalate

Peroxide

• O₂²⁻: Peroxide

Thio- Ions

• SCN⁻: Thiocyanate (thio = sulfur)
• S₂O₃²⁻: Thiosulfate

Conclusion

• Familiarity with these ions is crucial for chemistry classes.
• Memorize these common ions for class success and ease in problem-solving.