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 Periodic Table of Elements. Each entry contains the atomic number, chemical symbol, and atomic mass to two decimal places on elements where data is available. Undefined cells contain a space. Row ...

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

Developing the periodic table The periodic table was developed by grouping elements with similar properties. This, together with a later arrangement by atomic weight, led to a repeating pattern of ...