All are non metal
Found in vII a group
All have 7 electrons in outer most shell
They need 1 electron to complete their octet
All react vigorously with alkali metal
They all are found in diatomic form
Form salts
They are reactive
Having low melting and boiling point which increases down the group
At room temperature they are found in all states such as flourine chlorine as gas , bromine as liquid and iodine as solid
Read more on Brainly.in - https://brainly.in/question/4838662#readmore