Quick answerSodium (Na) is an alkali metal with atomic number 11 and an atomic mass of 22.99 (2023), in group 1, period 3. It was discovered by Humphry Davy in 1807. It is used for table salt production and sodium vapour street lighting. Its electron configuration is [Ne] 3s1.
Sodium is a soft metal that explodes on contact with water, yet as half of table salt it is essential to every meal and every cell in your body. Street lights glow orange from sodium vapour, soap is made with sodium hydroxide, and the same compound unblocks drains. Your nerves literally run on tiny pulses of sodium ions.
Key facts
| Symbol | Na |
|---|---|
| Atomic number | 11 |
| Atomic mass | 22.99 (IUPAC standard atomic weight, 2023) |
| Category | alkali metal |
| Group | 1 |
| Period | 3 |
| Block | s-block |
| Electron configuration | [Ne] 3s1 |
| Discovered | Humphry Davy, 1807 |
| Uses | table salt production, sodium vapour street lighting, soap and detergent manufacturing, glass production, chemical manufacturing |
Overview
Sodium is a soft, silvery alkali metal that bursts into flame on contact with water, yet as half of table salt it is essential to every meal and every cell in your body. It has atomic number 11, an atomic mass of 22.99, and the electron configuration [Ne] 3s1, with a single outer electron it gives up readily. It sits in group 1, period 3 of the periodic table. Humphry Davy isolated it in 1807 by passing an electric current through molten soda, and named it after soda, the substance it came from. Sodium never occurs as a free metal in nature, because it reacts too quickly; it is found instead in compounds, above all sodium chloride, common salt, in the sea and in salt mines. Your body uses sodium ions to carry nerve signals, contract muscles and balance fluids, which is why both too little and too much salt are harmful. Industry uses sodium compounds widely: sodium hydroxide makes soap and unblocks drains, sodium vapour fills street lights with their orange glow, and sodium compounds go into glass, paper and detergents. Sodium is also the metal in the coolant of some nuclear reactors.
Frequently asked questions
What is sodium used for?
Sodium is best known as half of table salt, sodium chloride, which seasons food and preserves it. Its compounds make soap, glass, paper and detergents, and sodium hydroxide unblocks drains. Sodium vapour fills street lights with an orange glow, and liquid sodium cools some nuclear reactors. Your body also needs sodium for nerves and muscles.
What is the symbol for sodium?
The chemical symbol for sodium is Na, from its Latin name natrium, rather than from the English word sodium. It has atomic number 11 and a standard atomic mass of 22.99, and it sits in group 1 and period 3 of the periodic table. Humphry Davy isolated it in 1807 by passing an electric current through molten soda.
What is the atomic number of sodium?
Sodium has atomic number 11, so it is the eleventh element in the periodic table. Its atom holds eleven protons and eleven electrons, and its standard atomic mass is 22.99. It is an alkali metal in group 1 and period 3, with the electron configuration [Ne] 3s1, a single electron in its outer shell.
Is sodium a metal?
Yes, sodium is a metal, an alkali metal in group 1 of the periodic table. It is soft enough to cut with a knife, silvery when cut, and so reactive that it is stored under oil to keep it away from air and water. It never occurs as a metal in nature, but only in compounds such as table salt.
Why does sodium explode in water?
Sodium explodes in water because it reacts violently with it, releasing hydrogen gas and a great deal of heat. The heat ignites the hydrogen, and the reaction speeds up as the metal melts and exposes fresh surface. The result is a burst of flame and sometimes a small explosion, which is why sodium is stored under oil.
Quick quiz
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Keep exploring
- Periodic table — all 118 elements
- Lithium (Li) — another alkali metal, atomic number 3
- Potassium (K) — another alkali metal, atomic number 19
- Rubidium (Rb) — another alkali metal, atomic number 37
- Caesium (Cs) — another alkali metal, atomic number 55
- Francium (Fr) — another alkali metal, atomic number 87
Sources & last updated
- CIAAW — Standard Atomic Weights
- PubChem Periodic Table
- Wikipedia — Timeline of chemical element discoveries
Last updated: . Figures are shown with their year; where sources disagree, the value is left out rather than estimated.