13 2 · 8 · 3

Aluminium, Al, element 13

Post-transition metal· Period 3· Group 13· p-block

Configuration [Ne]3s²3p¹

Atomic weight: 26.9815Da
Phase: solid
Density: 2.7g/cm³
Melting point: 933.473K 660.32 °C
Boiling point: 2,792.15K 2,519 °C
Electronegativity: 1.61

Silvery-white lustrous metallic element of group 3 of the periodic table. Highly reactive but protected by a thin transparent layer of the oxide which quickly forms in air. There are many alloys of aluminum, as well as a good number of industrial uses. Makes up 8.1% of the Earth's crust, by weight. Isolated in 1825 by H.C. Oersted. 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 aluminium

Atomic weight The standard atomic weight. For an element with no stable isotope, the mass of its longest-lived isotope.: 26.98154Da; Source: mendeleev
Electron configuration: [Ne]3s²3p¹; Source: mendeleev
Uncertainty of the atomic weight: 7×10⁻⁷Da; Source: mendeleev
Electron configuration in full The electron configuration with the noble-gas core written out.: 1s²2s²2p⁶3s²3p¹; Source: Worked outfrom electron configuration
Electrons in each shell Counted from the electron configuration, from the first shell outward.: 2 · 8 · 3; 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	0.409	12.591
2s	4.7864	8.2136
2p	4.0366	8.9634
3s	8.8828	4.1172
3p	8.9344	4.0656