Periodic table

This interactive periodic table shows all 118 elements, coloured by type. Pick any element to see its atomic number, standard atomic mass (IUPAC values, rounded), group, period, block, electron configuration in shorthand, Pauling electronegativity and its state at room temperature. You can search by name, symbol or atomic number, or light up one family, such as the halogens, or one block at a time.

1. Click or tap an element to see its details.
2. Type a name, symbol or atomic number in the search box. Press Enter to jump to the first match.
3. Use Highlight to light up one type of element, such as the noble gases. Click it again to clear it.
4. Use Block to show the s, p, d or f block.
5. With the keyboard, move around the table with the arrow keys.

• The group number tells you the outer electrons for groups 1 and 2, and the last digit does the same for groups 13 to 18: chlorine in group 17 has 7.
• Electronegativity rises across a period and falls down a group, which is why fluorine has the highest value.
• Masses in square brackets belong to radioactive elements. They show the mass number of the longest-lived isotope, not an average.
• Chromium and copper break the usual filling order: they take one electron from 4s to half fill or fill the 3d subshell.

Where do the atomic masses come from?

They are IUPAC standard atomic weights, rounded to about five significant figures. For elements with no stable isotopes, the value in brackets is the mass number of the longest-lived isotope.

Why do the lanthanides and actinides sit in separate rows?

They are the f-block. Putting them inside period 6 and 7 would make the table very wide, so they are drawn underneath. The gaps in group 3 show where they belong.

Why do some elements have no electronegativity?

Helium, neon and argon form no compounds, and the heaviest elements have only been made a few atoms at a time, so there is no measured value.