26 2 · 8 · 14 · 2

Iron, Fe, element 26

Transition metal· Period 4· Group 8· d-block

Configuration [Ar]3d⁶4s²

Atomic weight: 55.845Da
Phase: solid
Density: 7.87g/cm³
Melting point: 1,811.15K 1,538 °C
Boiling point: 3,134.15K 2,861 °C
Electronegativity: 1.83

Silvery malleable and ductile metallic transition element. Has nine isotopes and is the fourth most abundant element in the earth's crust. Required by living organisms as a trace element (used in hemoglobin in humans.) Quite reactive, oxidizes in moist air, displaces hydrogen from dilute acids and combines with nonmetallic elements. Description from mendeleev.

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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 iron

Atomic weight The standard atomic weight. For an element with no stable isotope, the mass of its longest-lived isotope.: 55.845Da; Source: mendeleev
Electron configuration: [Ar]3d⁶4s²; Source: mendeleev
Uncertainty of the atomic weight: 0.002Da; Source: mendeleev
Electron configuration in full The electron configuration with the noble-gas core written out.: 1s²2s²2p⁶3s²3p⁶3d⁶4s²; Source: Worked outfrom electron configuration
Electrons in each shell Counted from the electron configuration, from the first shell outward.: 2 · 8 · 14 · 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.

Subshell	Screening σ	Effective charge Z − σ
1s	0.619	25.381
2s	7.401	18.599
2p	3.9112	22.0888
3s	12.3239	13.6761
3p	13.2221	12.7779
3d	14.8202	11.1798
4s	20.566	5.434