56 - Barium alkaline earth metal
Discovered by Carl Wilhelm Scheele in 1808
Barium is a chemical element with symbol Ba and atomic number 56. It is the fifth element in Group 2, a soft silvery metallic alkaline earth metal. Because of its high chemical reactivity barium is never found in nature as a free element.
H He Li Be B C N O F Ne Na Mg Al Si P S Cl Ar K Ca Sc Ti V Cr Mn Fe Co Ni Cu Zn Ga Ge As Se Br Kr Rb Sr Y Zr Nb Mo Tc Ru Rh Pd Ag Cd In Sn Sb Te I Xe Cs Ba La Ce Pr Nd Pm Sm Eu Gd Tb Dy Ho Er Tm Yb Lu Hf Ta W Re Os Ir Pt Au Hg Tl Pb Bi Po At Rn Fr Ra Ac Th Pa U Np Pu Am Cm Bk Cf Es Fm Md No Lr Rf Db Sg Bh Hs Mt Ds Rg Cn Nh Fl Mc Lv Ts Og
57-71 La-Lu Lanthanides
89-103 Ac-Lr Actinides
| Shell | Electrons | Orbitals |
|---|---|---|
| 1 | 2 | 2 in 1s |
| 2 | 8 | 2 in 2s + 6 in 2p |
| 3 | 18 | 2 in 3s + 6 in 3p + 10 in 3d |
| 4 | 18 | 2 in 4s + 6 in 4p + 10 in 4d |
| 5 | 8 | 2 in 5s + 6 in 5p |
| 6 | 2 | 2 in 6s |
137 u Atomic Mass
2.8 Å Atomic Radius
2.17k K Boiling Point
2.15 Å Covalent Radius
3.51 g/cm³ Density
14 Electron Affinity
0.89 Electronegativity
5.21 eV First Ionization Energy
1k K Melting Point
6 Number of Shells
2 Electron Valency
56 Atomic Number
2, 8, 18, 18, 8, 2 Electron Shell Occupations
0.204 J/(g K) Specific Heat