Table 20.5 The Group 17 elements nce connguration: ns Molar Melting Boiling Density mass, point, point, g cm ame Symbol g /m at25°C Normal form* 9 fluorine F 19.00 -220 188 151 almost colorless gas(O,) 17 chlorine Cl 35.45 101 34 1.66′ yellow-green gas 35 bromine Br 7991 59 3.12 red-brown liquid 33 iodine 126.90 114 184 4.95 purple-black nonmetallic solid 85 astatine At 210 300 350. nonmetallic solid Normal form means the appearance and state of the element at 25C and 1 atm. For the liquid at its boiling point Radioactive