17 2 · 8 · 7

Chlorine, Cl, element 17

Halogen· Period 3· Group 17· p-block

Configuration [Ne]3s23p5

Atomic weight
35.45Da
Phase
gas
Density
0.002898g/cm³
Melting point
171.65K -101.5 °C
Boiling point
239.11K -34.04 °C
Electronegativity
3.16

Halogen element. Poisonous greenish-yellow gas. Occurs widely in nature as sodium chloride in seawater. Reacts directly with many elements and compounds, strong oxidizing agent. Discovered by Karl Scheele in 1774. Humphrey David confirmed it as an element in 1810. 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 chlorine

Atomic weight The standard atomic weight. For an element with no stable isotope, the mass of its longest-lived isotope.
35.45Da
Source: mendeleev
Electron configuration
[Ne]3s23p5
Source: mendeleev
Electron configuration in full The electron configuration with the noble-gas core written out.
1s22s22p63s23p5
Source: Worked outfrom electron configuration
Electrons in each shell Counted from the electron configuration, from the first shell outward.
2 · 8 · 7
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.

SubshellScreening σEffective charge Z − σ
1s0.476116.5239
2s5.569611.4304
2p4.006812.9932
3s9.93177.0683
3p10.88396.1161