Vision (Definition) Vision is a feature of a person's brain that allows him to see. He must have normal eyes, optic nerves (that stretch from the eyes to the back of his brain), and visual cortex (the vision center in the brain), in order to see properly. An ophthalmologist is a doctor specializing in vision. ...Read more.
The halogens or halogen elements (/ËhÃ¦lÉdÊÉn, ËheÉª-, -loÊ-, -ËdÊÉn/) are a group in the periodic table consisting of five chemically related elements: fluorine (F), chlorine (Cl), bromine (Br), iodine (I), and astatine (At). The artificially created element 117 (ununseptium) may also be a halogen.
Group 7, the Halogens. The halogens â some reactions Displacement reactions Halogen compounds Group 7, the Halogens The halogens â some reactions Displacement reactions Halogen compounds Group 17âThe Halogen Group All the elements in Group 17 are nonmetals except for astatine, which is a radioactive metalloid.roup 7, the Halogens. The halogens â some reactions Displacement reactions Halogen compounds Group 7, the Halogens The halogens â some reactions Displacement reactions Halogen compounds Group 17âThe Halogen Group All the elements in Group 17 are nonmetals except for astatine, which is a radioactive metalloid.