A halogen in this form may be produced homolytically by applying ultraviolet light to a halogen gas, and can then be used to halogenate alkanes in a chain reaction. In reaction mechanisms involving them, single-headed arrows are likely to be necessary. In the atmosphere, ozone is broken down by reacting with them. A hydroxyl one would be written "O H dot". Superoxide dismutase scavenges one of these chemicals, and vitamins A and E scavenge precursors to them, as do many other antioxidants. One theory proposes that the buildup of these substances over time is the main cause of aging. For 10 points, name these reactive 
A halogen in this form may be produced homolytically by applying ultraviolet light to a halogen gas, and can then be used to halogenate alkanes in a chain reaction. In reaction mechanisms involving them, single-headed arrows are likely to be necessary. In the atmosphere, ozone is broken down by reacting with them. A hydroxyl one would be written "O H dot". Superoxide dismutase scavenges one of these chemicals, and vitamins A and E scavenge precursors to them, as do many other antioxidants. One theory proposes that the buildup of these substances over time is the main cause of aging. For 10 points, name these reactive neutral chemicals that have unpaired electrons.
A halogen in this form may be produced homolytically by applying ultraviolet light to a halogen gas, and can then be used to halogenate alkanes in a chain reaction.
free radicals