Interactive periodic table of elements
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Click any element to see its atomic number, relative atomic mass, electron configuration, group and period, state at room temperature, melting and boiling points, density and when it was discovered. Search by name, symbol or atomic number, or highlight a family such as the alkali metals or the halogens. For the common elements, the card also shows the rounded mass used on GCSE data sheets. The data comes from PubChem, run by the US National Library of Medicine.
How the table is organised
Elements are in order of atomic number, the number of protons in the nucleus. Each row is a period: elements in the same period have the same number of occupied electron shells. Each column is a group: elements in the same group have the same number of electrons in their outer shell, which is why they react in similar ways. The two rows at the bottom (lanthanides and actinides) belong in periods 6 and 7; they're placed below to keep the table a sensible width.
The groups you need for GCSE and IGCSE
| Group | Name | Key facts |
|---|---|---|
| 1 | Alkali metals | One outer electron; react with water to make hydrogen and an alkali; more reactive down the group |
| 7 | Halogens | Seven outer electrons; exist as pairs of atoms (Cl₂); less reactive down the group |
| 0 (18) | Noble gases | Full outer shell, so very unreactive; boiling points rise down the group |
| 3 to 12 | Transition metals | Form coloured compounds, ions with different charges, and act as catalysts |
Metals are on the left and in the middle; non-metals are on the right. The staircase of metalloids between them includes silicon and germanium.
Relative atomic mass
The relative atomic mass () is the average mass of an element's atoms compared with one twelfth of a carbon-12 atom, taking into account how common each isotope is. That's why chlorine's is about 35.5: chlorine is a mixture of chlorine-35 and chlorine-37. GCSE data sheets round most values to whole numbers (except chlorine 35.5 and copper 63.5), which is what you should use in exams. For elements with no stable isotopes, the value shown is the mass of the most stable or best-known isotope.
To add up atomic masses for a compound, use the relative formula mass calculator.
Electron configuration
The configuration shows how electrons fill the shells and sub-shells. PubChem writes it in the full sub-shell form used at A level and beyond, using the previous noble gas as shorthand: sodium is [Ne]3s1. At GCSE you write the number of electrons in each shell instead: sodium is 2,8,1. To get the GCSE form, count the electrons in each shell: [Ne] is 2,8, then one more in the third shell.
Trends to know
- Down group 1: atoms get bigger, the outer electron is further from the nucleus and more easily lost, so reactivity increases.
- Down group 7: atoms get bigger, it's harder to gain an electron, so reactivity decreases.
- Across a period: elements change from metals to non-metals.
For revision across the whole course, see our GCSE chemistry revision guide.
Frequently asked questions
How many elements are there?
118 have been discovered and named, from hydrogen (1) to oganesson (118). All of them are in this table.
Which atomic mass should I use in exams?
The one on the data sheet or periodic table your exam board gives you. For most elements it's a whole number; chlorine is 35.5 and copper is 63.5.
Where does the data come from?
PubChem's periodic table, from the US National Library of Medicine. Melting and boiling points are converted from kelvin to degrees Celsius.
Why are two rows separate at the bottom?
The lanthanides and actinides belong in periods 6 and 7. They're shown underneath so the table isn't too wide.
Is anything I type sent to a server?
No. Everything runs in your browser, and nothing you type is sent to TutorAura.
Sources
- Periodic Table of Elements. PubChem, National Library of Medicine.
- GCSE Chemistry (8462) specification: subject content. AQA.
- Cambridge IGCSE Chemistry 0620 syllabus for 2026, 2027 and 2028. Cambridge International.
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