Sodium

Sodium is a chemical element wi the symbol Na (frae Laitin: natrium) an atomic nummer 11. It is a saft, siller-white, heichly reactive metal an is a member o the alkali metals; its anly stable isotope is ²³Na. The free metal daes nae occur in naitur, but insteid must be prepared frae its compoonds; it wis first isolatit bi Humphry Davy in 1807 bi the electrolysis o sodium hydroxide. Sodium is the saxt maist abundant element in the Yird's crust, an exists in numerous minerals sic as feldspars, sodalite an rock salt. Mony sauts o sodium are heichly watter-soluble, an thair sodium haes been leached bi the action o watter sae that chloride an sodium (NaCl) are the maist common dissolved elements bi wicht in the Yird's bodies o oceanic watter.

Sodium, ₁₁Na

Sodium
Appearance	sillery white metallic
Standard atomic weight Ar, std(Na)	7001229897692800000♠22.98976928(2)[1]
Sodium in the periodic cairt
Hydrogen Helium Lithium Beryllium Boron Carbon Nitrogen Oxygen Fluorine Neon Sodium Magnesium Aluminium Silicon Phosphorus Sulfur Chlorine Argon Potassium Calcium Scandium Titanium Vanadium Chromium Manganese Airn Cobalt Nickel Capper Zinc Gallium Germanium Arsenic Selenium Bromine Krypton Rubidium Strontium Yttrium Zirconium Niobium Molybdenum Technetium Ruthenium Rhodium Palladium Siller (element) Cadmium Indium Tin Antimony Tellurium Iodine Xenon Caesium Barium Lanthanum Cerium Praseodymium Neodymium Promethium Samarium Europium Gadolinium Terbium Dysprosium Holmium Erbium Thulium Ytterbium Lutetium Hafnium Tantalum Tungsten Rhenium Osmium Iridium Platinum Gowd Mercur (element) Thallium Leid (element) Bismuth Polonium Astatine Radon Francium Radium Actinium Thorium Protactinium Uranium Neptunium Plutonium Americium Curium Berkelium Californium Einsteinium Fermium Mendelevium Nobelium Lawrencium Rutherfordium Dubnium Seaborgium Bohrium Hassium Meitnerium Darmstadtium Roentgenium Copernicium Ununtrium Flerovium Ununpentium Livermorium Ununseptium Ununoctium Li ↑ Na ↓ K neon ← sodium → magnesium
Atomic nummer (Z)	11
Group	group 1 (alkali metals)
Period	period 3
Block	s-block
Element category	Alkali metal
Electron confeeguration	[Ne] 3s1
Electrons per shell	2,8,1
Pheesical properties
Phase at STP	solit
Meltin pynt	370.944 K ​(97.794 °C, ​208.029 °F)
Bylin pynt	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
Creetical pynt	(extrapolatit) 2573 K, 35 MPa
Heat o fusion	2.60 kJ/mol
Heat o vapourisation	97.42 kJ/mol
Molar heat capacity	28.230 J/(mol·K)
Vapour pressur P (Pa) 1 10 100 1 k 10 k 100 k at T (K) 554 617 697 802 946 1153
Atomic properties
Oxidation states	−1, +1 strangly basic
Electronegativity	Pauling scale: 0.93
Ionisation energies	(more)
Atomic radius	empirical: 186 pm
Covalent radius	166±9 pm
Van der Waals radius	227 pm
Spectral lines o sodium
Ither properties
Naitural occurrence	primordial
Creestal structur	​body-centred cubic (bcc)
Speed o soond 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 n Ω·m (at 20 °C)
Magnetic orderin	paramagnetic[2]
Young's modulus	10 GPa
Shear modulus	3.3 GPa
Bulk modulus	6.3 GPa
Mohs haurdness	0.5
Brinell haurdness	0.69 MPa
CAS Nummer	7440-23-5
History
Diskivery	Humphry Davy (1807)
First isolation	Humphry Davy (1807)
Main isotopes o sodium
Iso­tope Abun­dance Hauf-life (t1/2) Decay mode Pro­duct 22Na trace 2.602 y β+→γ 0.5454 22Ne* 1.27453(2)[3] 22Ne ε→γ - 22Ne* 1.27453(2) 22Ne β+ 1.8200 22Ne 23Na 100% stable
* = excited state
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Sodium wis first isolatit bi Humphry Davy in 1807 bi the electrolysis o sodium hydroxide. Amang mony ither uisefu sodium compoonds, sodium hydroxide is uised in saip manufactur, an sodium chloride (edible saut) is a de-icin augent an a nutrient for ainimals includin humans.

Sodium is an essential element for aw ainimals an some plants. Sodium ions are the major cation in the extracellular fluid (ECF) an as sic are the major contreibutor tae the ECF osmotic pressur an ECF compartment vollum. Loss o watter frae the ECF compartment increases the sodium concentration, a condeetion cried hypernatremia. Isotonic loss o watter an sodium frae the ECF compairtment decreases the size o that compartment in a condeetion cried ECF hypovolemia.

Bi means o the sodium-potassium pump, leevin human cells pump three sodium ions oot o the cell in exchynge for twa potassium ions pumped in; comparin ion concentrations athort the cell membrane, inside tae ootside, potassium meisurs aboot 40:1, an sodium, aboot 1:10. In nerve cells, the electrical chairge athort the cell membrane enables transmeession o the nerve impulse—an action potential—when the chairge is dissipatit; sodium plays a key role in that activity.