Jodi

Kemiallinen merkki: I
Järjestysluku: 53
Kategoria: halogeenit
Ryhmä: 17
Jakso: 5
Lohko: p
Moolimassa: 126,90447 g/mol
Elektronia kuorilla: 2, 8, 18, 18, 7
CAS-numero: 7553-56-2
Olomuoto: kiinteä
Tiheys: 4,933 kg/l (lähellä huoneenlämpöä)
Sulamispiste: 386,85 K (113,7 °C, 236,66 °F)
Kiehumispiste: 457,4 K (184,3 °C, 363,7 °F)
Kiderakenne: orthorhombic
Hapetusluvut: 1, 5, 7
Elektronegatiivisuus: 2,66 (Pauling-asteikko)
Nimen alkuperä: iodes
Nimen tarkoitus: a Greek word which means 'violet' due to its color
Faktoja:
- is the second least reactive of the halogens, and the second most electropositive halogen
- does not occur in the free state in nature
- iodine and its compounds are primarily used in medicine, photography, and dyes
- its compounds, the iodides, are very soluble in water, and the element is concentrated in seawater
- the element is required in trace amounts by all animals and some plants, being the heaviest element commonly used by living organisms (only
- iodine is a famous tester for starch - it dyes the starch blue
- its main role in animal biology is as constituents of the thyroid hormones, thyroxine (T4) and triiodothyronine (T3)
- excess iodine has symptoms similar to those of iodine deficiency - commonly encountered symptoms are abnormal growth of the thyroid gland and disorders in functioning and growth of the organism as a whole