9 2 · 7

Fluorine, F, element 9

Halogen· Period 2· Group 17· p-block

Configuration [He]2s22p5

Atomic weight
18.9984Da
Phase
gas
Density
0.001553g/cm³
Melting point
53.48K -219.67 °C
Boiling point
85.04K -188.11 °C
Electronegativity
3.98

A poisonous pale yellow gaseous element belonging to group 17 of the periodic table (The halogens). It is the most chemically reactive and electronegative element. It is highly dangerous, causing severe chemical burns on contact with flesh. Fluorine was identified by Scheele in 1771 and first isolated by Moissan in 1886. 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 fluorine

Atomic weight The standard atomic weight. For an element with no stable isotope, the mass of its longest-lived isotope.
18.9984Da
Source: mendeleev
Electron configuration
[He]2s22p5
Source: mendeleev
Uncertainty of the atomic weight
6×10−9Da
Source: mendeleev
Electron configuration in full The electron configuration with the noble-gas core written out.
1s22s22p5
Source: Worked outfrom electron configuration
Electrons in each shell Counted from the electron configuration, from the first shell outward.
2 · 7
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
1s0.34998.6501
2s3.87245.1276
2p3.95.1