Periodic Table

What it's for

Look up the elements: where each one sits in the table, its atomic number and mass, electron configuration and physical properties. The table can be coloured by category, block or a property such as density, which shows trends across the table at a glance. A molar mass calculator works out the mass of a formula.

For example, when you are checking a boiling point for a chemistry lesson, or working out how heavy a mole of copper sulphate is.

How to use it

Choose an element, with the mouse or the arrow keys (Enter or Space shows its facts below the table). Find an element takes a name, symbol or atomic number, dims the others, and Enter opens the first match. Colour by changes the colours: a property is shown from light (low) to dark (high), with its value in each square, and a dashed square means there is no value. The choice is remembered in the browser.

Molar mass of a formula takes formulas such as H2SO4, Ca(OH)2 or CuSO4·5H2O, with ( ), [ ] or { } brackets and a hydrate after a dot, · or *. Capitals matter: Co is cobalt, CO is carbon and oxygen. Copy a link to this input keeps the colouring and the formula.

Example

Choose Try an example, which fills in:

CuSO4·5H2O

The molar mass is 249.691 g/mol, with the share each element contributes listed under it.

Good to know

The facts come from PubChem’s periodic table (National Library of Medicine), with no descriptive text, and are only as good as that list: some masses are given to few digits (lithium as 7.0, iron as 55.84), so molar masses can differ in the last digit from a table you use elsewhere, and the elements without a value show “No data”. Atomic radius is the van der Waals radius in picometres. The lanthanides and actinides sit below the table with no group. Charges, isotopes and the Hill order for formulas aren’t handled. Check anything you rely on, such as a lab calculation, against your textbook.