chemical element with symbol Na and atomic number 11 From Wikipedia, the free encyclopedia
Sodium is a chemical element with an atomic number of 11. Its symbol is Na (from its Latin name natrium). It is an alkali metal. Although sodium has many isotopes, most decay in a short time. Because of this, all sodium in nature (mainly found in seawater) is of the isotope 11Na23. The atomic mass of sodium is 22.9898.
![]() | ||||||||||||||||||||||||||
Sodium | ||||||||||||||||||||||||||
---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
Appearance | silvery white metallic | |||||||||||||||||||||||||
Standard atomic weight Ar°(Na) | ||||||||||||||||||||||||||
22.98976928(2)[1] | ||||||||||||||||||||||||||
Sodium in the periodic table | ||||||||||||||||||||||||||
| ||||||||||||||||||||||||||
Group | group 1: hydrogen and alkali metals | |||||||||||||||||||||||||
Period | period 3 | |||||||||||||||||||||||||
Block | s-block | |||||||||||||||||||||||||
Electron configuration | [Ne] 3s1 | |||||||||||||||||||||||||
Electrons per shell | 2, 8, 1 | |||||||||||||||||||||||||
Physical properties | ||||||||||||||||||||||||||
Phase at STP | solid | |||||||||||||||||||||||||
Melting point | 370.944 K (97.794 °C, 208.029 °F) | |||||||||||||||||||||||||
Boiling point | 1156.090 K (882.940 °C, 1621.292 °F) | |||||||||||||||||||||||||
Density (near r.t.) | 0.968 g/cm3 | |||||||||||||||||||||||||
when liquid (at m.p.) | 0.927 g/cm3 | |||||||||||||||||||||||||
Critical point | 2573 K, 35 MPa (extrapolated) | |||||||||||||||||||||||||
Heat of fusion | 2.60 kJ/mol | |||||||||||||||||||||||||
Heat of vaporization | 97.42 kJ/mol | |||||||||||||||||||||||||
Molar heat capacity | 28.230 J/(mol·K) | |||||||||||||||||||||||||
Vapor pressure
| ||||||||||||||||||||||||||
Atomic properties | ||||||||||||||||||||||||||
Oxidation states | −1, 0,[2] +1 (a strongly basic oxide) | |||||||||||||||||||||||||
Electronegativity | Pauling scale: 0.93 | |||||||||||||||||||||||||
Ionization energies |
| |||||||||||||||||||||||||
Atomic radius | empirical: 186 pm | |||||||||||||||||||||||||
Covalent radius | 166±9 pm | |||||||||||||||||||||||||
Van der Waals radius | 227 pm | |||||||||||||||||||||||||
![]() | ||||||||||||||||||||||||||
Other properties | ||||||||||||||||||||||||||
Natural occurrence | primordial | |||||||||||||||||||||||||
Crystal structure | body-centered cubic (bcc) | |||||||||||||||||||||||||
Speed of sound thin rod | 3200 m/s (at 20 °C) | |||||||||||||||||||||||||
Thermal expansion | 71 µm/(m⋅K) (at 25 °C) | |||||||||||||||||||||||||
Thermal conductivity | 142 W/(m⋅K) | |||||||||||||||||||||||||
Electrical resistivity | 47.7 nΩ⋅m (at 20 °C) | |||||||||||||||||||||||||
Magnetic ordering | paramagnetic[3] | |||||||||||||||||||||||||
Molar magnetic susceptibility | +16.0·10−6 cm3/mol (298 K)[4] | |||||||||||||||||||||||||
Young's modulus | 10 GPa | |||||||||||||||||||||||||
Shear modulus | 3.3 GPa | |||||||||||||||||||||||||
Bulk modulus | 6.3 GPa | |||||||||||||||||||||||||
Mohs hardness | 0.5 | |||||||||||||||||||||||||
Brinell hardness | 0.69 MPa | |||||||||||||||||||||||||
CAS Number | 7440-23-5 | |||||||||||||||||||||||||
History | ||||||||||||||||||||||||||
Discovery and first isolation | Humphry Davy (1807) | |||||||||||||||||||||||||
Symbol | "Na": from New Latin natrium, coined from German Natron, 'natron' | |||||||||||||||||||||||||
Isotopes of sodium | ||||||||||||||||||||||||||
| ||||||||||||||||||||||||||
Sodium is a light-weight, silver-colored metal. Sodium is soft. It can easily be cut with a knife. When someone cuts it, the exposed part will become white over time. It reacts with air to form sodium hydroxide and sodium carbonate. Sodium is a little less dense than water. It floats and reacts instantly with water, producing hydrogen and sodium hydroxide. This reaction has a lot of heat, usually causing the hydrogen to light on fire. When this happens, sodium melts because of its low melting point. Sodium is highly reactive because it has one valence electron, which is easily removed.
Compared with other alkali metals, sodium is less reactive than potassium and more reactive than lithium.[6]
These are chemical compounds that contain sodium ions. Sodium only exists in one oxidation state: +1.
Sodium was discovered by Sir Humphrey Davy, an English scientist, in 1807. He created it by electrolyzing sodium hydroxide. Davy named the element after soda, a name for sodium hydroxide or sodium carbonate.
Scientists can use it in the creation of organic compounds. It is used in orange streetlights and lamps that emit ultraviolet light.
Sodium compounds are used in soaps, toothpaste, baking, and antacids.
The human body needs sodium ions, taken in the form of sodium chloride, to live. Too much of it can cause health problems. Many organisms in the ocean depend on the concentration of sodium ions in water to survive.
Sodium does not occur as an element in nature, because it is not stable enough. It exists only in chemical compounds. Sodium ions are found in the ocean and in the Earth's crust.
Sodium is normally made by electrolysis of sodium chloride, which is mined from the Earth's crust.
Seamless Wikipedia browsing. On steroids.
Every time you click a link to Wikipedia, Wiktionary or Wikiquote in your browser's search results, it will show the modern Wikiwand interface.
Wikiwand extension is a five stars, simple, with minimum permission required to keep your browsing private, safe and transparent.