8 2 · 6

Oxygen, O, element 8

Nonmetal· Period 2· Group 16· p-block

Configuration [He]2s²2p⁴

Atomic weight: 15.999Da
Phase: gas
Density: 0.001308g/cm³
Melting point: 54.36K -218.79 °C
Boiling point: 90.188K -182.96 °C
Electronegativity: 3.44

A colourless, odourless gaseous element belonging to group 16 of the periodic table. It is the most abundant element present in the earth's crust. It also makes up 20.8% of the Earth's atmosphere. For industrial purposes, it is separated from liquid air by fractional distillation. It is used in high temperature welding, and in breathing. It commonly comes in the form of Oxygen, but is found as Ozone in the upper atmosphere. It was discovered by Priestley in 1774. 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

4 of 5 fields have a value for oxygen

Atomic weight The standard atomic weight. For an element with no stable isotope, the mass of its longest-lived isotope.: 15.999Da; Source: mendeleev
Electron configuration: [He]2s²2p⁴; Source: mendeleev
Electron configuration in full The electron configuration with the noble-gas core written out.: 1s²2s²2p⁴; Source: Worked outfrom electron configuration
Electrons in each shell Counted from the electron configuration, from the first shell outward.: 2 · 6; Source: Worked outfrom electron configuration

No data uncertainty of the atomic weight.

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	0.3421	7.6579
2s	3.5084	4.4916
2p	3.5468	4.4532