Sodium Facts

Sodium is the eleventh element of the periodic table. These sodium facts contain chemical and physical data along with general information and history.

Basic Sodium Facts

Name: Sodium

Atomic Number: 11

Element Symbol: Na

Group: 1

Period: 3

Block: s

Element Family: alkali metal

Atomic Mass: 22.989 769 28(2)

Electron Configuration: [Ne]3s¹ (shorthand) or 1s²2s²2p⁶3s¹ (full)

Discovery: Sir Humphry Davy in 1807

Davy isolated sodium from sodium hydroxide using electrolysis. He found a shiny silver metal collecting at the electrode as he applied the current to his device.

Name Origin: Davy collected his new element from caustic soda, so he named it sodium. Swedish chemist Jöns Jakob Berzelius used the letters Na for sodium on his table of elements. Soda was known by its Latin name natrium after the Egyptian region of Natron Valley, a large supplier of caustic soda.

Isotopes:

Natural sodium is comprised of three isotopes: ²²Na, ²³Na and ²⁴Na. Nearly all sodium in nature is ²³Na. Seventeen radioactive isotopes have been produced under laboratory conditions ranging from ¹⁸Na to ³⁷Na.

²²Na
Sodium-22 is a stable isotope containing 11 neutrons. Only trace amounts of sodium-22 are found naturally. Sodium-22 is a radioactive isotope which decays into ²²Ne by β+ decay. Its half-life is 2.6 years.

²³Na
Sodium-23 is the only stable isotope of sodium. It contains 12 neutrons. 100% of natural sodium is sodium-23.

²⁴Na
Sodium-24 is a stable isotope containing 11 neutrons. Only trace amounts of sodium-24 are found naturally. Sodium-24 is a radioactive isotope which decays into ²⁴Mg by β- decay. Its half-life is 14.96 hours.

Physical Data

Density: 0.97 g/cm³

Melting Point: 370.944 K ​(97.794 °C, ​208.029 °F)

Boiling Point: 1156.090 K ​(882.940 °C, ​1621.292 °F)

Critical Point: 2573 K at 35 MPa (extrapolated)

State at 20ºC: Solid

Heat of Fusion: 2.60 kJ/mol

Heat of Vaporization: 97.42 kJ/mol

Molar Heat Capacity: 39.230 J/mol·K

Atomic Data

Atomic Radius: 2.27 Å

Covalent Radius: 1.66 Å

Van der Waals Radius:  2.27 Å

Electron Affinity: 52.867

Electronegativity: 0.93

1^st Ionization Energy: 495.845 kJ/mol

2^nd Ionization Energy: 4562.444 kJ/mol

3^rd Ionization Energy: 6910.28 kJ/mol

4^th Ionization Energy: 9543.36 kJ/mol

5^th Ionization Energy: 13353.6 kJ/mol

6^th Ionization Energy: 16612.85 kJ/mol

7^th Ionization Energy: 20117.2 kJ/mol

8^th Ionization Energy: 25496.25 kJ/mol

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

Fun Sodium Facts

• Sodium is a soft, malleable and shiny solid at room temperature.
• Sodium is less dense than water. Sodium metal will float on top of water.
• Sodium is soft enough to cut with a butter knife at room temperature.
• Sodium metal reacts with water to produce hydrogen gas. Occasionally, the hydrogen can ignite and give the appearance of sodium burning.
• Sodium burns with a bright yellow light. Sodium is used in fireworks to produce bright yellow sparks.
• Sodium is the sixth most abundant elements on Earth.
• Sodium is the ninth most abundant element in the human body. It accounts for 0.15% of your body.
• The most common sodium compound is sodium chloride, or table salt.
• Molten sodium is used as a heat transfer medium in some fast nuclear reactors.
• Yellow street lights are yellow because the light is produced by ionizing sodium vapor.
• One early method of obtaining caustic soda (sodium hydroxide) was soaking the ashes of plants in water.

Learn more about elements on the periodic table.