1, iodine is nonmetallic and has metallic luster;
2. Iodine is solid, easy to sublimate, and can be directly changed into gas without liquid.
3. Pure iodine vapor is dark blue, and mixed air is purple.
4. The color of iodized salt is mostly white crystals like salt, with a few exceptions, such as silver iodide is light yellow and copper iodide is golden yellow.
5. Iodine is slightly soluble in water, but more soluble in some organic solvents. The colors of iodine solution are purple, red, brown and dark brown. The darker the color, the more iodine is dissolved.
6. A large amount of iodine is toxic to people, and iodine vapor will seriously stimulate the eyes and nasal mucosa, causing people to die of poisoning.
Second, the introduction of iodine:
The atomic number of elemental iodine is 53, the relative atomic mass is 126.9, the symbol is I, and the English name is iodine, which belongs to VIIA family, the fifth cycle. It was discovered from seaweed by a French pharmacist named Bean Garnett Courtou in 18 1 1 year. ?
The density of elemental iodine is 4.93g/cm3, the melting point is 1 13.5℃, and the boiling point is 184.35℃. It is a metallic purple-black crystal, soluble in organic solvents but slightly soluble in water, easy to sublimate, fragile, toxic and corrosive.
Iodine can directly combine with most elements, but its activity is not strong, and its valence is-1,+1, +3, +5 and +7.
Extended data:
I. Causes and harms of iodine deficiency disorders:
Iodine is an essential raw material for the synthesis of thyroid hormone, which plays a very important role in the growth and development of infants, especially in the development of nervous system.
Iodine deficiency syndrome (IDD) is a series of damages caused by the lack of essential trace element iodine in the natural environment, including endemic goiter and endemic cretinism.
The biggest harm of iodine deficiency to human beings is that it affects brain development and can lead to mental and physical development disorders of children.
Cretinism can occur in areas with severe iodine deficiency, and mental retardation, nervous system damage and hypothyroidism can occur in areas with mild iodine deficiency. Because this kind of harm is not easy to be detected, it is more harmful to the quality of the population and social development.
Iodine deficiency is more harmful to pregnant women and fetuses, which can lead to premature delivery, abortion, stillbirth and fetal malformation. It leads to mental retardation, physical development and neuromotor disorders of the fetus. ?
Second, the application of iodine in the treatment of diseases:
Iodine 13 1 is actually a radioactive isotope of elemental iodine. The treatment of iodine 13 1 began in the 1940s and has been used up to now after numerous experiments.
It is a common treatment for hyperthyroidism patients, especially Graves hyperthyroidism patients. It has become the first choice for the treatment of hyperthyroidism in the United States.
Iodine 13 1 treatment principle;
Take hyperthyroidism as an example, the patient's thyroid production capacity is too strong and there are too many thyroid hormones. At this time, iodine 13 1 can be used to irradiate the thyroid gland, causing radioactive inflammation, thus destroying some thyroid tissues and reducing thyroid function, thus controlling hyperthyroidism.
When patients receive iodine 13 1 treatment, the unique iodine uptake function of thyroid nodules or thyroid cancer makes the drugs automatically focus on the focus after entering the body.