Periodic Table
Interactive periodic table with all 118 elements, color-coded by category.
About the Periodic Table of Elements
The Periodic Table of Elements is one of the most important references in chemistry and science. Developed by Dmitri Mendeleev in 1869, it organizes all known chemical elements by their atomic number and groups them by shared properties. The table consists of 18 groups (columns) and 7 periods (rows), with two additional rows for lanthanides and actinides. Each element is represented by its chemical symbol, atomic number, and atomic mass. The periodic table reveals patterns in element properties such as electronegativity, ionization energy, and atomic radius, making it an invaluable tool for understanding chemical behavior and predicting element properties.
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Frequently Asked Questions
What is the Periodic Table?▾
The Periodic Table is a tabular arrangement of chemical elements organized by atomic number, electron configuration, and recurring chemical properties. Elements in the same column (group) share similar characteristics.
How many elements are in the Periodic Table?▾
There are currently 118 confirmed elements in the Periodic Table, from Hydrogen (1) to Oganesson (118). Elements 1-94 occur naturally, while elements 95-118 are synthetic.
What are Lanthanides and Actinides?▾
Lanthanides (elements 57-71) and Actinides (elements 89-103) are two series of inner transition metals. They are placed separately below the main table to keep the table compact. Lanthanides are also called rare earth elements.