Group 7 = 7 electrons in the outer shell.
- They are all non-metals.
- They are all diatomic = molecules of two atoms.
- F2 not F, Cl2 not Cl, etc.
- They are all toxic vapors. i.e. they are poisonous.
- Fluorine, Chlorine, Bromine, iodine, astatine.
- Fluorine is a yellow gas.
- Chlorine is a green gas.
- Bromine is a dark red liquid.
- Iodine is a dark grey solid or a purple vapor.
- Astatine is probably black - but…