The chemical symbol for barium is Ba and its atomic number is 56.
We find it listed in the periodic table of elements in group 2 and 6 and block period s.
Barium belongs to the family alkaline earth metals such as eg Beryllium, Calcium, Magnesium, ...
This element is stable.
Barium came from the greek word barus which means heavy.
Atomic number (Z) 56
Group, block group 2 (alkaline earth metals), s-block
Period: period 6
Element category: alkaline earth metals
Standard atomic weight (±) (Ar): 137.327(7)
Electron configuration: [Xe] 6s2
per shell: 2, 8, 18, 18, 8, 2
Physical properties
Phase: solid
Melting point: 1000 K (727 °C, 1341 °F)
Boiling point: 2118 K (1845 °C, 3353 °F)
Density near r.t.: 3.51 g/cm3
when liquid, at m.p. 3.338 g/cm3
Heat of fusion: 7.12 kJ/mol
Heat of vaporization: 142 kJ/mol
Molar heat capacity 28.07 J/(mol•K)
Atomic properties
Oxidation states: +2, +1 (a strongly basic oxide)
Electronegativity: Pauling scale: 0.89
Ionization energies 1st: 502.9 kJ/mol
2nd: 965.2 kJ/mol
3rd: 3600 kJ/mol
Atomic radius empirical: 222 pm
Covalent radius: 215±11 pm
Van der Waals radius: 268 pm
Crystal structure: body-centered cubic
Speed of sound thin rod 1620 m/s (at 20 °C)
Thermal expansion 20.6 µm/(m•K) (at 25 °C)
Thermal conductivity: 18.4 W/(m•K)
Electrical resistivity: 332 nΩ•m (at 20 °C)
Magnetic ordering: paramagnetic
Young's modulus: 13 GPa
Shear modulus 4.9 GPa
Bulk modulus 9.6 GPa
Mohs hardness: 1.25
CAS Number 7440-39-3