Interactive periodic table with category filters, subcategories, color coding, and state information for the 118 elements.
The periodic table arranges the chemical elements by increasing atomic number and reflects recurring patterns in their properties. Lanthanides and actinides are shown separately below the main grid, which is the familiar layout used in most modern chemistry references.
The modern table grew out of 19th-century attempts to organize elements by repeating behavior, with Dmitri Mendeleev’s 1869 version becoming the landmark design. Today it is the standard framework for comparing elements, tracing trends, and finding basic atomic data quickly.
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Periodic Table FAQ
What is the periodic table?
The periodic table is a chart of the chemical elements arranged by atomic number. Elements in the same column often share similar chemical behavior because their outer electron structures are related.
Who created the modern periodic table?
Dmitri Mendeleev is credited with the first widely accepted periodic table in 1869. His version grouped the known elements by recurring properties and left gaps for elements that had not yet been discovered.
Why are lanthanides and actinides shown separately?
They are usually displayed below the main table to keep the layout compact and readable. They still belong in the main sequence of elements, but the split format makes the table easier to scan.
How many elements are on the periodic table?
There are 118 confirmed elements. They run from hydrogen, which has atomic number 1, to oganesson, which has atomic number 118.
Why is the periodic table arranged by atomic number?
Atomic number reflects the number of protons in the nucleus and gives the modern order of the elements. This arrangement explains the repeating pattern of chemical properties better than older mass-based systems.