Iodine

Iodine (I)

Atomic Number: 53
Atomic Weight: 126.90
Melting Point: 113.50
Boiling Point: 184.35
Specific Gravity: 4.93 (solid)
Valence(s): -1,3,5, or 7
Iodine was discovered by Courtois in 1811. It is a dark blue solid that evaporates at room temperature into a violet gas that is harmful to humans. Salt contains iodine because it is essential in preventing goiter, an enlargement of the thyroid gland. Iodine is industrially used in dyes, in photography, and as a catalyst. [LM] {RW}