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LITHOEN

Chemical element

Sodium

A major element of alkali and plagioclase feldspars, readily mobilised by fluids and among the first elements lost during chemical weathering.

Classification

atomic number
11
symbol
Na
block
s

How this record is known

3
Settled consensus
Cited as the accepted position of the discipline.

3 of 3 claims on this page cite at least one registered source. Counts describe how each statement is known, not how likely it is to be true.

What Lithoen records

Each claim states how it is known and cites its evidence.

Established11 protons

Sodium has atomic number 11: its nucleus contains 11 protons, and that is what makes it sodium.

  • definition basis: Atomic number is definitional: an atom with a different proton count is a different element, whatever else it shares.

Evidence support: Supported by the cited evidence one source

Evidence: Commission on Isotopic Abundances and Atomic Weights (IUPAC) 2024 Primary authority

Established22.989769 u

The standard atomic weight of sodium is 22.98976928(2), a single value because its isotopic composition does not vary appreciably between normal materials.

  • definition basis: CIAAW Standard Atomic Weights 2024; the parenthesised digits are the uncertainty in the last figures as published.
  • precision note: A property of the element as found in normal materials, not the mass of any individual atom.

Evidence support: Supported by the cited evidence one source

Evidence: Commission on Isotopic Abundances and Atomic Weights (IUPAC) 2024 Primary authority

In the knowledge graph

  • Sodium essential constituent of Albite

Record last updated 2026-09-06. Corrections follow the published corrections policy; superseded claims are retained, never silently edited.