Halogens

Key findings of the report:

• Oceans, along with absorbing carbon dioxide and moderating the climate, also cool the planet by releasing short-lived halogens such as chlorine, bromine and iodine.
• The short-lived halogens from the ocean reduce warming by depleting ozone.
• They increase methane’s lifetime in the atmosphere by destroying hydroxyl radicals (OH).
• They have increased the global methane burden by 14 per cent and 9 per cent for pre-industrial and present-day conditions.
• Halogens increase the levels of water vapour, a greenhouse gas in the atmosphere.
• The emission of halogen from the ocean is not the same across the world.
• Over continents, the emissions are small, while it is bigger in polar regions and some places with higher ozone levels.

Key facts about Halogens:

• The term Halogen in Greek means salt-producing because it reacts with many metals to produce salts.
• They are a group of elements located in Group 17 of the periodic table, which includes fluorine (F), chlorine (Cl), bromine (Br), iodine (I), and astatine (At).
• In 1826, Swedish chemist Jons Berzelius coined the term halogen for the entire group of elements. 
• Unlike metals, they exist in all three different states of matter in their standard state.
• For example, fluorine is found naturally as a gas, bromine as a liquid, and the larger iodine is found naturally as a solid.
• Reactivity: Halogens are the most reactive nonmetals on the periodic table and are powerful oxidising agents.