Compare Elements
Put any two to four elements side by side across seventeen properties — from atomic structure to melting points and everyday uses. Great for spotting group trends and settling “which is more reactive?” debates.
Pick at least two elements (or a preset above) to see the side-by-side comparison.
How to compare elements
Search for an element by name, symbol or atomic number and add it to the comparison, then add a second, third or fourth. The table fills in as you go and updates the page link, so you can copy it and send someone the exact comparison you are looking at. Elements are always listed in atomic-number order, which means it makes no difference whether you add carbon before boron or the other way around — you get the same, shareable result.
What you can see side by side
Each comparison lines up the properties that matter most for spotting patterns: atomic mass, electron configuration, atomic and ionic radius, electronegativity, ionization energy, density, melting and boiling points, state at room temperature, and typical uses. The clearest comparisons pick elements that share a group (a column) or a period (a row): compare sodium with potassium to see reactivity increase down a group, or fluorine with chlorine to watch atomic size grow while electronegativity falls. Where a value is genuinely unknown — common for synthetic elements — the table shows “Not available” rather than an invented number.
Frequently asked questions
How many elements can I compare at once?
Up to four. Two or three is usually clearest — pick elements from the same group or period to see trends in action.
Can I share a comparison?
Yes — the URL updates as you pick elements, and the “Copy share link” button gives you a link that reopens the exact same comparison.
Why do some values say “Not available”?
Some properties are unmeasured or unreliable for rare and synthetic elements. We show “Not available” rather than an invented number — see our editorial policy.