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 ...

The zigzag, staircase, line in the diagram of the periodic table above separates the metals, on the left, from non-metals, on the right. Hydrogen is a non-metal, but it is often put in the middle.

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 ...