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 ...

Want to learn more about this centerpiece of chemistry? Take your pick from this collection of links about elements and the periodic table! Build an element ball, solve periodic puzzles, and check out ...

Across a period from left to right, the covalent radius decreases. As you move from left to right across the periodic table, atoms have more electrons in their outer energy level and more protons ...