Cl
Chlorine · element 17
Diatomic Nonmetal · Gas at room temperature
Chlorine is a chemical element with symbol Cl and atomic number 17. It also has a relative atomic mass of 35.5. Chlorine is in the halogen group (17) and is the second lightest halogen following fluorine.
Key facts
Atomic mass
35.45 u
how heavy one atom is
Phase (room temp.)
Gas
Density
3.2 g/L
how tightly packed it is
Melting point
171.6 K (-102 °C)
when solid turns to liquid
Boiling point
239.11 K (-34 °C)
when liquid turns to gas
Period
3
its row in the periodic table
Group
17
its column in the periodic table
Block
P-block
the neighbourhood it lives in
Electronegativity
3.16
how strongly it pulls electrons
Electron configuration
[Ne] 3s2 3p5
where its electrons live
Shells
2 · 8 · 7
electrons in each layer, inside to out
Discovered by
Carl Wilhelm Scheele
who found it
Appearance
pale yellow-green gas
what it looks like
Source: Wikipedia