But how many of these elements do you know? Test your knowledge and compete with other Live Science readers to see who can ...

For elements in the first three periods of the periodic table (hydrogen - argon), the orbitals can simply ... For potassium and calcium, the 4s orbital dips in energy below the 3d orbitals, and so ...

The periodic table of chemical elements, often called the periodic table, organizes all discovered chemical elements in rows (called periods) and columns (called groups) according to increasing atomic ...

Electronegativity, an essential characteristic of all elements in the periodic table, measures an atom's ability to attract electrons towards itself within a chemical bond. This vital theoretical ...

On 17 February 1869, Russian chemist Dmitri Mendeleev jotted down the symbols for the chemical elements, putting them in order according to their atomic weights and inventing the periodic table.