Interactive periodic table with all 118 elements. Search by name, symbol, or atomic number. Click any element to view detailed information including atomic mass, electron configuration, and phase at room temperature.
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About the Periodic Table
The periodic table organizes all known chemical elements by their atomic number, electron configuration, and recurring chemical properties. First developed by Dmitri Mendeleev in 1869, the modern table contains 118 confirmed elements. Elements are arranged in 18 columns (groups) and 7 rows (periods), with the lanthanides and actinides displayed separately below the main table.
FAQ
Q: How are elements arranged in the periodic table?
A: Elements are arranged by increasing atomic number (number of protons). Rows are called periods and columns are called groups. Elements in the same group share similar chemical properties because they have the same number of valence electrons.
Q: What are lanthanides and actinides?
A: 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 it compact. Lanthanides are all metals with similar properties; most actinides are radioactive and synthetic.
Q: Why do noble gases rarely form compounds?
A: Noble gases (Group 18) have completely filled outer electron shells, making them extremely stable. This full valence shell means they have very low reactivity and rarely form chemical bonds, though some heavier noble gases like xenon can form compounds under extreme conditions.
Q: What is the heaviest element?
A: Oganesson (Og, element 118) is the heaviest known element. It was first synthesized in 2002 and named after physicist Yuri Oganessian. Only a few atoms have ever been produced, and its chemical properties are largely predicted rather than experimentally confirmed.
Q: What do the element categories mean?
A: Categories group elements by shared properties. Alkali metals are highly reactive soft metals. Transition metals are hard, dense metals with high melting points. Metalloids have properties between metals and nonmetals. Noble gases are inert. Halogens are highly reactive nonmetals that form salts with metals.