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• periodic table
  periodic table

  noun

  a table illustrating the periodic system, in which the chemical elements, formerly arranged in the order of their atomic weights and now according to their atomic numbers, are shown in related groups.
• Periodic Table
  Periodic Table

  A table in which the chemical elements are arranged in order of increasing atomic number. Elements with similar properties are arranged in the same column (called a group), and elements with the same number of electron shells are arranged in the same row (called a period).

periodic table

American  

[peer-ee-od-ik, peer-] / ˈpɪər iˈɒd ɪk, ˌpɪər- /

noun

Chemistry.

1. a table illustrating the periodic system, in which the chemical elements, formerly arranged in the order of their atomic weights and now according to their atomic numbers, are shown in related groups.

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periodic table British  

/ ˌpɪərɪˈɒdɪk /

noun

1. a table of the elements, arranged in order of increasing atomic number, based on the periodic law. Elements having similar chemical properties and electronic structures appear in vertical columns (groups)

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Periodic Table Scientific  

1. A table in which the chemical elements are arranged in order of increasing atomic number. Elements with similar properties are arranged in the same column (called a group), and elements with the same number of electron shells are arranged in the same row (called a period).

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Etymology

Origin of periodic table

First recorded in 1890–95

Example Sentences

The periodic table supposedly came to Dmitri Mendeleev in a dream.

From The Wall Street Journal • May 13, 2026

Every character has an adorable quirk or two, or at minimum owns a dorky T-shirt with a periodic table joke or a cartoon cat.

From Los Angeles Times • Mar. 18, 2026

Germanium and arsenic sit next to each other on the periodic table, making the compounds chemically similar but structurally distinct.

From Science Daily • Jan. 12, 2026

These include scandium, yttrium and the lanthanides, which account for 15 chemical elements in the periodic table.

From MarketWatch • Oct. 28, 2025

The periodic table and Jane Eyre and even the location of the Brown Pelican.

From "Okay for Now" by Gary D. Schmidt