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Naming Compounds Chemistry Practice

Pick the compound types, then answer names and formulas in the quiz or print a worksheet with an answer key. A new set every time.

The naming compounds practice is a free tool for chemistry naming practice. It generates problems on naming chemical compounds and writing formulas, with an on-screen quiz and a printable worksheet. It runs in your web browser with no sign-up, and nothing you create is uploaded or sent to a server.

You can choose from five types of compound: ionic compounds with fixed-charge metals, ionic compounds with transition metals, ionic compounds with polyatomic ions, molecular compounds with Greek prefixes, and acids. Each set can mix names and formulas, or focus on naming from a formula or writing a formula from a name. Use it for homework, test prep, or classroom practice.

How to use the naming compounds practice

  1. Tick one or more Types of compound: Ionic, fixed-charge metals; Ionic, transition metals with Roman numerals; Ionic with polyatomic ions; Molecular with Greek prefixes; or Acids.
  2. Pick a Question type: Mixed (names and formulas), Formula to name, or Name to formula.
  3. Set the Number of problems between 10 and 40.
  4. Open the Quiz tab and type each answer. Type formulas plainly, such as Fe2(SO4)3.
  5. Click Check answers to mark each answer Correct or Not quite and see your score. Use Show answer for one problem, or Show all answers for the full set. Use Start over to begin again.
  6. Open the Worksheet tab for a printable sheet: two columns of numbered problems with answer lines. Tick Include polyatomic ion list to add a reference box at the top and Include answer key page for the answers, and pick US Letter or A4.
  7. Click Download PDF to save a vector PDF that stays sharp at any zoom and prints at true size. Click Print to open the browser’s print dialog with only the sheet.

Clicking New version gives you a new set. Copy link copies a link that reopens the same settings and the saved set.

How do you name ionic compounds?

Ionic compounds are named by their metal (cation) and nonmetal (anion). Name the metal first, then the nonmetal with the ending -ide: NaCl is sodium chloride and MgO is magnesium oxide. Polyatomic ions keep their own names, so Ca(OH)2 is calcium hydroxide and (NH4)2SO4 is ammonium sulfate.

Metals that can form more than one ion, such as most transition metals plus Sn and Pb, show the charge in Roman numerals. FeCl3 is iron(III) chloride, Cu2O is copper(I) oxide, and SnCl4 is tin(IV) chloride. Metals with only one possible charge, like sodium, do not get a Roman numeral. Mercury(I) is the Hg2 2+ ion, so mercury(I) chloride is Hg2Cl2.

Writing a formula from an ionic name reverses the process. Write each ion with its charge, then balance the charges so the total is zero. Aluminum oxide has Al3+ and O2−, so the formula is Al2O3. Calcium nitrate has Ca2+ and NO3−, so you need two nitrate ions: Ca(NO3)2.

How do you name covalent (molecular) compounds with prefixes?

Molecular compounds made of two nonmetals use Greek prefixes to show how many atoms of each element are present: mono 1, di 2, tri 3, tetra 4, penta 5, hexa 6, hepta 7, octa 8, nona 9, and deca 10. Name the first element with its prefix, leaving out “mono” if there is only one atom, then name the second element with its prefix and the -ide ending. CO2 is carbon dioxide.

Two rules cause most mistakes. Leave out “mono” on the first element, so CO2 is carbon dioxide, not monocarbon dioxide. Also drop the a or o at the end of the prefix before “oxide”: CO is carbon monoxide, N2O4 is dinitrogen tetroxide, and P4O10 is tetraphosphorus decoxide.

Writing a molecular formula from a name uses the same prefixes as subscripts. Dinitrogen tetroxide has two nitrogen atoms and four oxygen atoms, so the formula is N2O4.

Frequently asked questions

How do you name acids?

Binary acids that start with hydrogen use hydro-, the nonmetal stem, and -ic acid, so HCl is hydrochloric acid and H2S is hydrosulfuric acid. For oxyacids, an -ate ion gives -ic acid (HNO3 is nitric acid), and an -ite ion gives -ous acid (HNO2 is nitrous acid). Acids are named as acids in water, not as hydrogen compounds.

How do I type a formula in the quiz?

Type the formula plainly, using normal digits for subscripts and parentheses for groups, such as Fe2(SO4)3. Capital letters matter: Co is cobalt and CO is carbon monoxide. Names ignore capital letters and extra spaces.

Is there an answer key?

Yes. In the quiz, use Show answer for one problem or Show all answers for the whole set. For paper, the worksheet tab includes an optional answer key page that you can add before you download or print.

Which name spellings does the quiz accept?

The quiz accepts common alternatives, such as iron (III) or ferric and ferrous, aluminium for aluminum, sulphate for sulfate, and bicarbonate. You do not need to match one exact spelling.

Is the naming compounds practice free to use?

Yes. It runs in your web browser with no sign-up, and nothing you create is uploaded or sent to a server.