20 2 · 8 · 8 · 2

Calcium, Ca, element 20

Alkaline earth metal· Period 4· Group 2· s-block

Configuration [Ar]4s2

Atomic weight
40.078Da
Phase
solid
Density
1.54g/cm³
Melting point
1,115.15K 842 °C
Boiling point
1,757.15K 1,484 °C
Electronegativity
1

Soft grey metallic element belonging to group 2 of the periodic table. Used a reducing agent in the extraction of thorium, zirconium and uranium. Essential element for living organisms. 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 calcium

Atomic weight The standard atomic weight. For an element with no stable isotope, the mass of its longest-lived isotope.
40.078Da
Source: mendeleev
Electron configuration
[Ar]4s2
Source: mendeleev
Uncertainty of the atomic weight
0.004Da
Source: mendeleev
Electron configuration in full The electron configuration with the noble-gas core written out.
1s22s22p63s23p64s2
Source: Worked outfrom electron configuration
Electrons in each shell Counted from the electron configuration, from the first shell outward.
2 · 8 · 8 · 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
1s0.52719.473
2s6.223613.7764
2p3.958616.0414
3s10.39859.6015
3p11.34178.6583
4s15.6024.398