why group 17 elements called halogens...
Group 17 elements are called halogens because halogen is a Greek word which means 'salt producing'. Halogens include fluorine, chlorine, bromine, iodine and astatine. They all are non-metals. They react with metals to form compounds called salts.
For example:
2Na + Cl2 2NaCl (s)
For example:
2Na + Cl2 2NaCl (s)