Polyatomic Ions
Type the formula or name of each polyatomic ion. Accepts flexible formatting (e.g., SO4^2- or SO₄²⁻).
Common Questions
What is a polyatomic ion?
A polyatomic ion is a group of covalently bonded atoms that carries an overall electric charge. It acts as a single unit in chemical formulas and reactions. Examples: sulfate (SO4 2-), nitrate (NO3-), ammonium (NH4+).
What are the most common polyatomic ions to memorize?
Key ions: sulfate (SO4 2-), nitrate (NO3-), phosphate (PO4 3-), carbonate (CO3 2-), hydroxide (OH-), ammonium (NH4+), acetate (C2H3O2-), permanganate (MnO4-), dichromate (Cr2O7 2-), and cyanide (CN-).
How do the -ate and -ite suffixes work?
The -ate suffix has more oxygen atoms; -ite has fewer. For example: sulfate (SO4 2-) vs. sulfite (SO3 2-), nitrate (NO3-) vs. nitrite (NO2-). The charge stays the same; only the oxygen count changes.
How do you use polyatomic ions in chemical formulas?
Write the polyatomic ion as a unit. If you need more than one, put it in parentheses with a subscript: Ca(NO3)2 means two nitrate ions. Never change the internal formula of the ion.