24 2 · 8 · 13 · 1

Chromium, Cr, element 24

Transition metal· Period 4· Group 6· d-block

Configuration [Ar]3d54s1

Atomic weight
51.9961Da
Phase
solid
Density
7.15g/cm³
Melting point
2,180.15K 1,907 °C
Boiling point
2,944.15K 2,671 °C
Electronegativity
1.66

Hard silvery transition element. Used in decorative electroplating. Discovered in 1797 by Vauquelin. 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 chromium

Atomic weight The standard atomic weight. For an element with no stable isotope, the mass of its longest-lived isotope.
51.9961Da
Source: mendeleev
Electron configuration
[Ar]3d54s1
Source: mendeleev
Uncertainty of the atomic weight
6×10−4Da
Source: mendeleev
Electron configuration in full The electron configuration with the noble-gas core written out.
1s22s22p63s23p63d54s1
Source: Worked outfrom electron configuration
Electrons in each shell Counted from the electron configuration, from the first shell outward.
2 · 8 · 13 · 1
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
1s0.586223.4138
2s7.016216.9838
2p3.924820.0752
3s11.632212.3678
3p12.53411.466
3d14.24349.7566
4s18.86685.1332