38 2 · 8 · 18 · 8 · 2

Strontium, Sr, element 38

Alkaline earth metal· Period 5· Group 2· s-block

Configuration [Kr]5s2

Atomic weight
87.62Da
Phase
solid
Density
2.64g/cm³
Melting point
1,050.15K 777 °C
Boiling point
1,650.15K 1,377 °C
Electronegativity
0.95

Soft yellowish metallic element, belongs to group 2 of the periodic table. Highly reactive chemically. Sr-90 is present in radioactive fallout and has a half-life of 28 years. Discovered in 1798 by Klaproth and Hope, isolated in 1808 by Humphry Davy. 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 strontium

Atomic weight The standard atomic weight. For an element with no stable isotope, the mass of its longest-lived isotope.
87.62Da
Source: mendeleev
Electron configuration
[Kr]5s2
Source: mendeleev
Uncertainty of the atomic weight
0.01Da
Source: mendeleev
Electron configuration in full The electron configuration with the noble-gas core written out.
1s22s22p63s23p63d104s24p65s2
Source: Worked outfrom electron configuration
Electrons in each shell Counted from the electron configuration, from the first shell outward.
2 · 8 · 18 · 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
1s0.808937.1911
2s10.098227.9018
2p3.969634.0304
3s15.336222.6638
3p15.832422.1676
3d15.273822.7262
4s24.555613.4444
4p26.06811.932
5s31.92956.0705