How to Learn the First 20 Elements
The first 20 elements — hydrogen through calcium — are the backbone of school chemistry. Know these in order, with their symbols, and most of GCSE / intro chemistry suddenly makes sense. This short deck and a classic mnemonic get you there fast.
There are 20 cards in the deck below. You can read through them, practise them right here with the flip-card player, and then save the deck to study properly with spaced repetition — the method that makes them stick for months, not minutes.
Why the first 20 elements of the periodic table is hard to memorize (and the fix)
The order matters (it is atomic number 1 to 20), and a few symbols do not match the name — sodium is Na and potassium is K. Learning them in sequence, not just as a random set, is what makes them stick.
The fix is active recall plus spaced repetition. Instead of re-reading the list (which feels productive but barely works), you test yourself — pull each answer out of memory — and you review each card on a schedule that stretches over time. Every time you successfully recall a fact, the memory gets stronger and the next review is pushed further out. That's how you go from "I saw it once" to "I just know it."
The fastest way to learn the first 20 elements of the periodic table
- Break it into small batches. Twenty in order — learn them in two batches of ten (H to Ne, then Na to Ca), then join the halves.
- Test, don't re-read. Look at the question, say the answer out loud before flipping the card. The little struggle to recall is what builds the memory — a smooth re-read does almost nothing.
- Review on a schedule. Spaced repetition shows you each card right before you'd forget it. Get one right and it comes back in a few days, then a week, then a month. Miss one and it comes back sooner.
- Keep sessions short and daily. Five to ten minutes a day beats a two-hour cram every time. Consistency is the whole game.
One fact per card. Learn atomic number, name and symbol together so you can answer whichever the question asks for.
The full deck: the First 20 Elements
Here's every card in the set. Practise them above, or save the deck and let spaced repetition schedule your reviews automatically.
| Element | Symbol |
|---|---|
| What is the chemical symbol for Hydrogen? | H |
| What is the chemical symbol for Helium? | He |
| What is the chemical symbol for Lithium? | Li |
| What is the chemical symbol for Beryllium? | Be |
| What is the chemical symbol for Boron? | B |
| What is the chemical symbol for Carbon? | C |
| What is the chemical symbol for Nitrogen? | N |
| What is the chemical symbol for Oxygen? | O |
| What is the chemical symbol for Fluorine? | F |
| What is the chemical symbol for Neon? | Ne |
| What is the chemical symbol for Sodium? | Na |
| What is the chemical symbol for Magnesium? | Mg |
| What is the chemical symbol for Aluminium? | Al |
| What is the chemical symbol for Silicon? | Si |
| What is the chemical symbol for Phosphorus? | P |
| What is the chemical symbol for Sulfur? | S |
| What is the chemical symbol for Chlorine? | Cl |
| What is the chemical symbol for Argon? | Ar |
| What is the chemical symbol for Potassium? | K |
| What is the chemical symbol for Calcium? | Ca |
Save this deck and actually remember it
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Study this deck free →FAQ: learning the first 20 elements of the periodic table
How long does it take to learn the first 20 elements of the periodic table?
Most people can lock in the first 20 elements of the periodic table within one to three weeks of short daily sessions. With spaced repetition doing 10–20 cards a day, you'll recognise them within days and recall them reliably within a couple of weeks.
What's the best way to memorize the first 20 elements of the periodic table?
Active recall plus spaced repetition. Test yourself instead of re-reading, and review on a schedule that spaces the cards out over time. Flashcards are built for exactly this — which is why the deck above is the fastest path.
Is this deck free?
Yes. You can practise all 20 cards on this page for free with no account. Sign up (also free) to save the deck and let spaced repetition schedule your reviews so it sticks long-term.