41.2 Variation in Properties of the Halogens (SB p.83) Some physical properties of the halogens Halogen Colour and state at room temperature and pressure Atomic radius (nm) Ionic radius (nm) Fluorine Chlorine Bromine Iodine Astatine Pale yellow gas Greenish yellow gas Reddish brown liquid Violet black solid – 0.072 0.099 0.114 0.133 – 0.133 0.181 0.195 0.216 –