Study tool

Periodic table

All 118 elements. Click an element to learn about it, or tap a colour to highlight a family.

Find an element

Click any element to see its details here.

Atomic masses are standard atomic weights rounded for school use. Numbers in [brackets] are the mass number of the most stable known isotope.

How to read the periodic table

Atomic number (top) is the number of protons. Elements are arranged in order of it.
Groups are the 18 columns. Elements in a group have the same number of outer electrons, so they behave alike. Group 1 metals all react strongly with water.
Periods are the 7 rows. The period number is the number of electron shells.
Metals are on the left, non-metals on the right, and metalloids sit along the zig-zag line between them.