Sodium Element (Na or Atomic Number 11)

Chemical & Physical Properties

Baking soda spilling out of a measuring spoon
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Symbol: Na

Atomic Number: 11

Atomic Weight: 22.989768

Element Classification: Alkali Metal

CAS Number: 7440-23-5

Periodic Table Location

Group: 1

Period: 3

Block: s

Electron Configuration

Short Form: [Ne]3s1

Long Form: 1s22s22p63s1

Shell Structure: 2 8 1

Discovery of Sodium

Discovery Date: 1807

Discoverer: Sir Humphrey Davy [England]

Name: Sodium derives its name from the Medieval Latin 'sodanum' and the English name 'soda.' The element symbol, Na, was shortened from the Latin name 'Natrium.' Swedish chemist Berzelius was the first to use the symbol Na for sodium in his early periodic table.

History: Sodium does not usually appear in nature on its own, but its compounds have been used by people for centuries. Elemental sodium was not discovered until 1808. Davy isolated sodium metal using electrolysis from caustic soda or sodium hydroxide (NaOH).

Physical Data

State at room temperature (300 K): Solid

Appearance: soft, bright silvery-white metal

Density: 0.966 g/cc

Density at Melting Point: 0.927 g/cc

Specific Gravity: 0.971 (20 °C)

Melting Point: 370.944 K

Boiling Point: 1156.09 K

Critical Point: 2573 K at 35 MPa (extrapolated)

Heat of Fusion: 2.64 kJ/mol

Heat of Vaporization: 89.04 kJ/mol

Molar Heat Capacity: 28.23 J/mol·K

Specific Heat: 0.647 J/g·K (at 20 °C)

Atomic Data

Oxidation States: +1 (most common), -1

Electronegativity: 0.93

Electron Affinity: 52.848 kJ/mol

Atomic Radius: 1.86 Å

Atomic Volume: 23.7 cc/mol

Ionic Radius: 97 (+1e)

Covalent Radius: 1.6 Å

Van der Waals Radius: 2.27 Å

First Ionization Energy: 495.845 kJ/mol

Second Ionization Energy: 4562.440 kJ/mol

Third Ionization Energy: 6910.274 kJ/mol

Nuclear Data

Number of isotopes: 18 isotopes are known. Only two are naturally occurring.

Isotopes and % abundance: 23Na (100), 22Na (trace)

Crystal Data

Lattice Structure: Body-Centered Cubic

Lattice Constant: 4.230 Å

Debye Temperature: 150.00 K

Sodium Uses

Sodium chloride is important for animal nutrition. Sodium compounds are used in the glass, soap, paper, textile, chemical, petroleum, and metal industries. Metallic sodium is used in manufacturing of sodium peroxide, sodium cyanide, sodamide, and sodium hydride. Sodium is used in preparing tetraethyl lead. It is used in the reduction of organic esters and preparation of organic compounds. Sodium metal may be used to improve the structure of some alloys, to descale metal, and to purify molten metals. Sodium, as well as NaK, an alloy of sodium with potassium, are important heat transfer agents.

Miscellaneous Facts

  • Sodium is the 6th most abundant element in the Earth's crust, making up approximately 2.6% of the earth, air, and oceans.
  • Sodium is not found free in nature, but sodium compounds are common. The most common compound is sodium chloride or salt.
  • Sodium occurs in many minerals, such as cryolite, soda niter, zeolite, amphibole, and sodalite.
  • The top three countries that produce sodium are China, United States, and India. Sodium metal is mass produced by electrolysis of sodium chloride.
  • The D lines of sodium's spectrum account for the dominant yellow color of the un.
  • Sodium is the most abundant alkali metal.
  • Sodium floats on water, which decomposes it to evolve hydrogen and form the hydroxide. Sodium may ignite spontaneously on water. It does not usually ignite in air at temperatures below 115°C
  • Sodium burns with a bright yellow color in a flame test.
  • Sodium is used in fireworks to make an intense yellow color. The color is sometimes so bright it overwhelms other colors in a firework.


  • CRC Handbook of Chemistry & Physics, (89th Ed.).
  • Holden, Norman E. History of the Origin of the Chemical Elements and Their Discoverers, 2001.
  • “National Institute of Standards and Technology.” NIST.
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Your Citation
Helmenstine, Anne Marie, Ph.D. "Sodium Element (Na or Atomic Number 11)." ThoughtCo, Feb. 16, 2021, Helmenstine, Anne Marie, Ph.D. (2021, February 16). Sodium Element (Na or Atomic Number 11). Retrieved from Helmenstine, Anne Marie, Ph.D. "Sodium Element (Na or Atomic Number 11)." ThoughtCo. (accessed March 28, 2023).