Element Symbol Definition in Chemistry

Some symbols have changed over time

Periodic Table of the Elements

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In chemistry, an element symbol usually refers to the one- or two-letter abbreviation for a chemical element, though the term also can be applied to the alchemical symbols.

Key Takeaways: Element Symbol Definition

  • An element symbol is a one- or two-letter abbreviation for a chemical element name.
  • When a symbol consists of two letters, the first letter is always capitalized, while the second letter is lowercase.
  • Element symbols also can refer to alchemy symbols for the elements or to the symbols used to describe isotopes.

Examples

Examples of modern element symbols include H for hydrogen, He for helium, and Ca for calcium. The first letter of an element symbol is capitalized, while the second letter is lowercase.

An example of a deprecated element symbol is Cb for columbium, the former name of the element niobium, or Nb. However, some elements retain their old symbols when they change names. For example, Ag is the element symbol for silver, which was once called argentum.

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