Sodium

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Sodium is a soft, waxy, silvery reactive metal never found unbound in nature, and a chemical element (symbol Na) with an atomic number of 11 and atomic weight of 22.989770.

 

General
Name, symbol, number sodium, Na, 11
Chemical series alkali metals
Group, period, block 1, 3, s
Appearance silvery white
Standard atomic weight 22.98976928(2)g·mol-1
Electron configuration [Ne] 3s1
Electrons per shell 2, 8, 1
Physical properties
Phase solid
Density (near r.t.) 0.968 g·cm-3
Liquid density at m.p. 0.927 g·cm-3
Melting point 370.87 K
(97.72 °C, 207.9 °F)
Boiling point 1156 K
(883 °C, 1621 °F)
Critical point (extrapolated)
2573 K, 35 MPa
Heat of fusion 2.60 kJ·mol-1
Heat of vaporization 97.42 kJ·mol-1
Heat capacity (25 °C) 28.230 J·mol-1·K-1
Vapor pressure
P/Pa 1 10 100 1 k 10 k 100 k
at T/K 554 617 697 802 946 1153
Atomic properties
Crystal structure cubic body centered
Oxidation states 1
(strongly basic oxide)
Electronegativity 0.93 (Pauling scale)
Ionization energies
(more)
1st: 495.8 kJ·mol-1
2nd: 4562 kJ·mol-1
3rd: 6910.3 kJ·mol-1
Atomic radius 180 pm
Atomic radius (calc.) 190 pm
Covalent radius 154 pm
Van der Waals radius 227 pm
Miscellaneous
Magnetic ordering paramagnetic
Electrical resistivity (20 °C) 47.7 nΩ·m
Thermal conductivity (300 K) 142 W·m-1·K-1
Thermal expansion (25 °C) 71 µm·m-1·K-1
Speed of sound (thin rod) (20 °C) 3200 m/s
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 registry number 7440-23-5

 

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