Lithium

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Lithium is the simplest alkali metal, the lightest solid element, and the third lightest chemical element (symbol Li) with an atomic number of 3. Trace amounts of lithium are present in the oceans and within various organisms. Lithium ion Li+ when ingested has a neurological effect, making some lithium salts useful as a class of mood stabilizing drugs.

 

General
Name, symbol, number lithium, Li, 3
Chemical series alkali metals
Group, period, block 1, 2, s
Appearance silvery white/grey
Standard atomic weight 6.941(2)g·mol-1
Electron configuration 1s2 2s2
Electrons per shell 2, 1
Physical properties
Phase solid
Density (near r.t.) 0.534 g·cm-3
Liquid density at m.p. 0.512 g·cm-3
Melting point 453.69 K
(180.54 °C, 356.97 °F)
Boiling point 1615 K
(1342 °C, 2448 °F)
Critical point (extrapolated)
3223 K, 67 MPa
Heat of fusion 3.00 kJ·mol-1
Heat of vaporization 147.1 kJ·mol-1
Heat capacity (25 °C) 24.860 J·mol-1·K-1
Vapor pressure
P/Pa 1 10 100 1 k 10 k 100 k
at T/K 797 885 995 1144 1337 1610
Atomic properties
Crystal structure body centered cubic
Oxidation states 1
(strongly basic oxide)
Electronegativity 0.98 (Pauling scale)
Ionization energies 1st: 520.2 kJ·mol-1
2nd: 7298.1 kJ·mol-1
3rd: 11815.0 kJ·mol-1
Atomic radius 145 pm
Atomic radius (calc.) 167 pm
Covalent radius 134 pm
Van der Waals radius 182 pm
Miscellaneous
Magnetic ordering paramagnetic
Electrical resistivity (20 °C) 92.8 nΩ·m
Thermal conductivity (300 K) 84.8 W·m-1·K-1
Thermal expansion (25 °C) 46 µm·m-1·K-1
Speed of sound (thin rod) (20 °C) 6000 m/s
Young's modulus 4.9 GPa
Shear modulus 4.2 GPa
Bulk modulus 11 GPa
Mohs hardness 0.6
CAS registry number 7439-93-2

 

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