4 2 · 2

Beryllium, Be, element 4

Alkaline earth metal· Period 2· Group 2· s-block

Configuration [He]2s2

Atomic weight
9.01218Da
Phase
solid
Density
1.85g/cm³
Melting point
1,560.15K 1,287 °C
Boiling point
2,741.15K 2,468 °C
Electronegativity
1.57

Grey metallic element of group 2 of the periodic table. Is toxic and can cause severe lung diseases and dermatitis. Shows high covalent character. It was isolated independently by F. Wohler and A.A. Bussy in 1828. Description from mendeleev.

Back to the table
The outermost shell: the valence electronsThe inner shellsThe nucleus One bead for each electron, on the ring of its shell, counted from the nucleus out. The rings turn at their own pace; the model is Bohr's picture of the atom, which places electrons in shells but not on true orbits.

Atomic properties

5 of 5 fields have a value for beryllium

Atomic weight The standard atomic weight. For an element with no stable isotope, the mass of its longest-lived isotope.
9.012183Da
Source: mendeleev
Electron configuration
[He]2s2
Source: mendeleev
Uncertainty of the atomic weight
5×10−7Da
Source: mendeleev
Electron configuration in full The electron configuration with the noble-gas core written out.
1s22s2
Source: Worked outfrom electron configuration
Electrons in each shell Counted from the electron configuration, from the first shell outward.
2 · 2
Source: Worked outfrom electron configuration

Screening of each subshell

Clementi's screening constants: how much of the nucleus's charge the other electrons hide from an electron in each subshell. What is left is the effective nuclear charge it feels.

SubshellScreening σEffective charge Z − σ
1s0.31523.6848
2s2.0881.912