Halogens are the family in Group 7 of the periodic table, consisting of the elements fluorine, chlorine, bromine, iodine, and astatine.
General Properties
Halogens are non-metals. At room temperature they can vary from gas to solid, and their colors can range from pale yellow to grayish-black. They have low melting and boiling points and are poor conductors of heat and electricity. They are the most reactive of the nonmetals, and are diatomic. They are poisonous.
They have seven valence electrons and therefore have high electronegativities. They are highly reactive especially with alkali metals and alkaline earth metals.
They have seven valence electrons and therefore have high electronegativities. They are highly reactive especially with alkali metals and alkaline earth metals.
Group trends
As you go down the group:
- their melting points increase
- their colors become darker
- they become less reactive
- their volatility decreases (the first two are gases, the bottom two are solids, and the rest in the middle are liquids)
- their melting points increase
- their colors become darker
- they become less reactive
- their volatility decreases (the first two are gases, the bottom two are solids, and the rest in the middle are liquids)
Chemistry The Study of Matter Prentice Hall p.684
http://www.bbc.co.uk/schools/gcsebitesize/science/add_ocr_pre_2011/periodic_table/group7rev1.shtml
http://www.onlinemathlearning.com/halogens.html
http://www.bbc.co.uk/schools/gcsebitesize/science/add_ocr_pre_2011/periodic_table/group7rev1.shtml
http://www.onlinemathlearning.com/halogens.html