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 ...

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 ...

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

The periodic table of elements (often known simply as the periodic table) has been helping scientists with their work for a little over 150 years. The handy visual reference guide organizes known ...

The modern periodic table, arranged in rows and columns, was first introduced by Dmitri Mendeleev in 1869. At the time, it included the known elements and their properties, but Mendeleev predicted ...