Final answer:
The polyatomic ion NO3- is known as the nitrate ion, which includes one nitrogen and three oxygen atoms with a negative one charge. Compounds with polyatomic ions are named with the cation first followed by the anion, like calcium nitrate for Ca(NO3)2. Polyatomic ions' formulas and charges must be memorized for proper naming and formula writing.
Step-by-step explanation:
The polyatomic ion NO3- is known as the nitrate ion. It consists of one nitrogen atom combined with three oxygen atoms and has an overall charge of 1- (minus one). When writing the names of compounds containing polyatomic ions like nitrate, the procedure is straightforward. The name of the cation is written first, followed by the name of the polyatomic anion. For instance, the compound NaNO3 would be named sodium nitrate, and Ca(NO3)2, where more than one nitrate ion is required to balance the calcium ion's charge, is named calcium nitrate.
Memorizing polyatomic ions, their formulas, names, and charges is essential for correctly naming and writing the formulas of compounds containing them. While some ions like NH4+ (ammonium) and H3O+ (hydronium) are positively charged, most polyatomic ions like NO3- (nitrate) are negatively charged. To denote more than one polyatomic ion in a compound formula, the ion is enclosed in parentheses with the appropriate subscript outside to indicate the number of ions needed, as seen in Fe(NO3)3, which translates to three nitrate ions combined with one iron(III) ion.