Section: STEM · ChemistryDifficulty: Easy
Periodic Table
USUK
A tabular arrangement of chemical elements ordered by atomic number and properties.
Also: Mendeleev table · element table
Definition
The periodic table is a systematic arrangement of the 118 known chemical elements organized by increasing atomic number, with elements grouped into rows (periods) and columns (groups) based on shared chemical properties. Elements in the same group have the same number of valence electrons and exhibit similar reactivity. The table was first developed by Dmitri Mendeleev in 1869 and has since been expanded as new elements were discovered.
Example
“All alkali metals in Group 1 of the periodic table, including lithium, sodium, and potassium, react vigorously with water to produce hydrogen gas and a metal hydroxide solution.”
Synonyms
- element table
- chart of elements
- Mendeleev table
Images
CC-licensed · free to useLoading images…
Video
Related Terms
- Atomic Number
- Valence Electrons
- Chemical Element
- Electron Configuration