Quiz Reference
The First Twenty Elements, and How to Remember Them
Published September 26, 2026 • 1 Views
Hydrogen to calcium in order, with symbols and atomic numbers, a mnemonic that actually sticks, and what each one is for.
Quiz questions about the periodic table almost always live in the first twenty. Learn these in order and you have covered most of what any general knowledge round will ask.
The first twenty
| # | Element | Symbol | Known for |
|---|---|---|---|
| 1 | Hydrogen | H | Lightest and most abundant element |
| 2 | Helium | He | Balloons; the only element found in the sun first |
| 3 | Lithium | Li | Batteries; lightest metal |
| 4 | Beryllium | Be | Light, stiff, used in aerospace |
| 5 | Boron | B | Borax, heat-resistant glass |
| 6 | Carbon | C | The basis of all known life |
| 7 | Nitrogen | N | 78% of the air |
| 8 | Oxygen | O | 21% of the air; breathing |
| 9 | Fluorine | F | Toothpaste; most reactive element |
| 10 | Neon | Ne | Signs that glow orange-red |
| 11 | Sodium | Na | Half of table salt |
| 12 | Magnesium | Mg | Burns bright white; in chlorophyll |
| 13 | Aluminium | Al | Cans, foil, aircraft |
| 14 | Silicon | Si | Sand, glass, computer chips |
| 15 | Phosphorus | P | Matches; bones and DNA |
| 16 | Sulfur | S | The rotten-egg smell |
| 17 | Chlorine | Cl | The other half of salt; pools |
| 18 | Argon | Ar | Inert filler in light bulbs |
| 19 | Potassium | K | Bananas; nerve signals |
| 20 | Calcium | Ca | Bones, teeth, chalk |
A mnemonic that sticks
Take the initials in order — H He Li Be B C N O F Ne Na Mg Al Si P S Cl Ar K Ca — and read them as a sentence:
"Harry He Likes Beer But Could Not Obtain Food. New Nations Might Also Sign Peace Security Clause. Arthur King Can."
It is nonsense, which is exactly why it works. Most people find they can reel off the first ten within a few minutes and the rest within a day.
Things people get wrong
- Helium was found in the sun before it was found on Earth, in the spectrum of an eclipse in 1868. It is named after Helios.
- Hydrogen is not a metal in ordinary conditions, despite sitting above the alkali metals.
- Aluminium and aluminum are the same element. The international spelling has the extra I; the American one does not.
- The lightest metal is lithium, not aluminium. Lithium floats on water.
- Fluorine, not chlorine, is the most reactive of all elements.