Na
Sodium
Element 11 · Alkali metal
Sodium (Na)
Sodium is a soft, silvery alkali metal that reacts violently with water. In compounds like table salt it is essential to all animal life.
- Alkali metal
- Period 3
- Group 1
- s-block
- solid at room temperature
Key properties
- Atomic mass
- 22.9898
- u
- Electron configuration
- [Ne] 3s1
- Melting point
- 97.8 °C
- 370.95 K
- Boiling point
- 882.9 °C
- 1,156 K
- Density
- 0.97 g/cm³
- Electronegativity
- 0.93
- Pauling
- Atomic radius
- 227 pm
- van der Waals
- 1st ionisation energy
- 5.139 eV
Compare with every element:Electronegativity chartAtomic radius chartIonisation energy chartDensity chart of the elementsMelting point chartElectron configuration chart
Did you know?
Notable facts about sodium
- 01
Davy isolated sodium by passing electricity through molten caustic soda.
- 02
Sodium is soft enough to cut with a butter knife.
- 03
Nerve signals depend on sodium ions moving across cell membranes.
Applications
What is sodium used for?
- Table salt (NaCl)
- Sodium-vapour street lamps
- Coolant in fast-breeder reactors
- Baking soda and glass making
History
Discovery & name origin
Discovered by
Year
Where
England
Name origin
English soda; the symbol Na comes from Latin natrium.
Atomic structure
Atomic properties
Atomic structure
Atomic properties
- Atomic number
- 11
- Atomic mass
- 22.9898 u
- Group
- 1
- Period
- 3
- Block
- s-block
- Electron configuration
- [Ne] 3s1
- Full configuration
- 1s2 2s2 2p6 3s1
- Electrons per shell
- 2, 8, 1
- Electronegativity (Pauling)
- 0.93
- Electron affinity
- 0.548 eV
- Atomic radius (van der Waals)
- 227 pm
- Stable isotopes
- 1
Oxidation states
Highlighted: common oxidation states (+1).
Successive ionisation energies
Energy to remove each electron in turn (kJ/mol). Big jumps show where a new, inner shell begins.
- 1st495.8
- 2nd4,562
- 3rd6,910.3
- 4th9,543
- 5th13,354
- 6th16,613
- 7th20,117
- 8th25,496
Physical
Physical properties & colour
Physical
Physical properties & colour
- State at 20 °C
- Solid
- Melting point
- 370.95 K · 97.8 °C · 208 °F
- Boiling point
- 1,156 K · 882.9 °C · 1,621.1 °F
- Density
- 0.97 g/cm³
- Molar heat capacity
- 28.23 J/(mol·K)
- Appearance
- Silvery white metallic
- CPK model colour
- Copied
The CPK colour is the convention used for this element’s atoms in molecular models.
FAQ
Sodium questions
What is Na on the periodic table?
Na is the symbol for sodium, element 11 on the periodic table. It sits in group 1, period 3, in the alkali metal category, and has an atomic mass of 22.9898.
What is the atomic number of sodium?
Sodium has atomic number 11, so every sodium atom has 11 protons in its nucleus. Its symbol is Na and its atomic mass is 22.9898.
Who discovered sodium?
Sodium was discovered by Humphry Davy in 1807 (England). The name comes from English soda; the symbol Na comes from Latin natrium.
What is sodium used for?
Sodium is used for: table salt (NaCl); sodium-vapour street lamps; coolant in fast-breeder reactors; baking soda and glass making.
Is sodium a metal?
Yes. Sodium is a alkali metal, one of the metallic elements.
What is the electron configuration of sodium?
The electron configuration of sodium is [Ne] 3s1. Its 11 electrons are arranged in shells as 2, 8, 1.