In the era of leaded gasoline, a compound made from ethylene (e-thuh-LEEN) and an element from this group was used to clean out engine cylinders.
The molecules selenorhodane (seh-leh-nor-HOH-dane) and thiocyanate (thai- oh-SAI-uh-nate) are sometimes called "pseudo-" members of this group, which exchanges one atom for another in the Finkelstein reaction. In the era of leaded gasoline, a compound made from ethylene (e-thuh-LEEN) and an element from this group was used to clean out engine cylinders. Another element from this group is in a solution which turns blue-black in the presence of starch, Lugol's solution, and another element from this group gives mustard gas and DDT their deadly potency. Freon contains two elements from this group, as do several other ozone depleting refrigerants. Containing the most electronegative element, name this group that includes astatine, iodine, chlorine, and fluorine.
The molecules selenorhodane (seh-leh-nor-HOH-dane) and thiocyanate (thai- oh-SAI-uh-nate)
halogens [accept Group 7A or Group 17]