Students learn to describe the pattern in atomic number, atomic mass and atomic radius. Trends on the Periodic Table: Students learn to describe the pattern in atomic number, atomic mass, atomic ...

Chemists use symbols and formulae to represent elements and compounds. Word equations and balanced chemical equations represent the changes that happen in chemical reactions. Mixtures - AQA There are ...

The covalent radius (a measure of how large individual atoms are) shows different trends if you are moving across a period or down a group. A comparison of the relative covalent radii of atoms is ...

In this video excerpt from NOVA's "Hunting the Elements," New York Times technology columnist David Pogue explores how the periodic table of elements took shape. Learn how the periodic table developed ...

Since the invention of the periodic table 150 years ago this month, scientists have worked to fill in the rows of elements and make sense of their properties. But researchers have also pursued a ...

For now, they're known by working names, like ununseptium and ununtrium — two of the four new chemical elements whose discovery has been officially verified. The elements with atomic numbers 113, 115, ...