Atomic mass quiz: which mass belongs to which element?
Practice the atomic masses (standard atomic weights) of the elements in both directions: pick the mass of a named element, then name the element behind a mass. The answer options are neighboring elements, so you have to think, not guess.
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How it works
Questions alternate between “pick the atomic mass” and “which element has this mass?”. Choose 4 or 6 answer options and a play style: 10 questions, as many as you can in 60 seconds, or keep going until you miss three. Your best score is saved in your browser.
Play it three ways: a classic round of 10 questions, a 60-second speed round (25 right answers earns a star), or survival, where you keep going until you miss three.
Tips
- Atomic mass is roughly double the atomic number for light elements: carbon is 6 and 12.011, oxygen is 8 and 15.999.
- Heavier elements have more extra neutrons, so the mass climbs faster than double: iron is 26 and 55.845, gold is 79 and 196.97.
- Masses are averages over each element’s natural isotopes, which is why chlorine is 35.45 rather than a whole number.
- Learn a few anchors by heart (H 1.008, C 12.011, N 14.007, O 15.999, Na 22.990, Cl 35.45) and the molar mass of almost any school compound follows.