What is the value of a barium

barium

Barium: characteristics

Atomic number:

56

Symbol:

Ba

Name (German / English):

Barium (official name according to IUPAC)

Group:

Alkaline earth metals

IUPAC group:

2 (old nomenclature: Group II A)

Period:

6

Dimensions (rounded):

137.33 u (rounded to the five significant digits)

Dimensions (exact):

137.327 u +/- 7 digit (s) [1]

Discoverer:

Davy

Discovery year:

1808

Occurrence:

Naturally

Frequency:

0.03% (percentage by mass of the earth's shell, i.e. the earth's crust / oceans up to a depth of 16 km)

CAS number [2]:

7440-39-3

Barium: atomic properties

Atomic radius (empirical):

215 pm

Atomic radius (calculated):

253 pm

Covalent radius:

198 pm

Atomic volume:

39.0 cm3/ mol

Ionization energies:

kJ / moleV
1.502.9 kJ / mol5.212 eV
2.965.2 kJ / mol10.004 eV
3.3600 kJ / mol37.311 eV

Oxidation numbers:

II

Electronegativity (Pauling):

0,89

Electronegativity (Allred / Rochow):

1

Ionic radius:

135 pm

Grid energy:

1.86 eV / particle

Number nat. Isotopes:

7

Number of stable isotopes:

7

Number of unstable isotopes:

15

Stable isotopes:

isotopefrequency
130Ba0,106%
132Ba0,101%
134Ba2,417%
135Ba6,592%
136Ba7,854%
137Ba11,23%
138Ba71,70%

Radioactive isotopes:

isotopeHalf-life
133Ba10.5a (i.e. years, from lt. annus)
148Ba0.64s

(The list contains only the 2 most important isotopes with known half-lives.)

Electron configuration:

[Xe] 6s2
OrbitalElectrons
1s2
2s2
2p6
3s2
3p6
3d10
4s2
4p6
4d10
4f0
5s2
5p6
5d0
5f0
6s2
6p0
6d0

Shell model:

  • 2 electrons in the outermost occupied shell
  • 8 electrons in the second to last occupied shell
  • 18 electrons in the occupied shell below

Barium: substance properties

Melting point:

1002 K (~ 728.85 ° C)

Boiling point:

2170 K (~ 1896.85 ° C)

State of aggregation:

fixed (under normal conditions)

Crystal structure:

body-centered cubic

Metal properties:

Metal (alkaline earth metal)

Specific heat of fusion:

8.01 kJ / mol

Specific heat of vaporization:

140.2 kJ / mol

Thermal conductivity:

18.4 W / m / K

Specific heat capacity:

0.204 J / gK

Specific density:

3.594 g / cm3
(under normal conditions)

Hardness (according to Mohs):

1,25


 
Remarks:
  1. 1 digit = least significant digit, i.e. 2.435 +/- 3 digits means 2.432 ... 2.438
  2. The "CAS Registry Number" is that of the element barium from Chemical Abstracts Service Assigned key number, which makes it easier to find specialist articles about this element in all publications and databases structured according to the CAS system.
    Legal notice: CAS registry number is a registered trademark of the American Chemical Society.