Halogens are highly reactive in nature. Fluorine for example is the most reactive of all elements. They have a number of important industrial and commercial applications. They have also been linked with issue of environmental concern including that of ozone depletion at high latitudes. The name for this group is in part derived from the Greek word Halos meaning salts.
|Element||Atomic number||Atomic weight||Boiling point||Density||Heat fusion||Heat vapour||Melting point||Specific heat capacity||Thermal conductivity|
|Bromine||35||79.91||331.16° K||3120 kg/m³||5.28 kJ/mol||14.99 kJ/mol||265.96° K|
|Chlorine||17||35.45||238.46° K||1560 kg/m³||3.22 kJ/mol||10.22 kJ/mol||172.16° K|
|Fluorine||9||19||84.96° K||1505 kg/m³||0.26 kJ/mol||3.16 kJ/mol||53.56° K|
|Iodine||53||126.9||456.16° K||4940 kg/m³||7.83 kJ/mol||21.78 kJ/mol||386.86° K|