1. named for the Greek word meaning ‘moon’ – selene.
2. found as either a silvery metallic substance or an amorphous red powder.
3. combustable in air.
4. may be used as a toner for photographic prints
5. essential for life, and used in many cellular processes. Keshan disease is caused by an absence of selenium.
6. toxic in high doses – selenosis is characterised by breath that smells like garlic amongst other symptoms
7. concentrated in the plant vetch (and makes animals act as if drunk when they eat it).
8. found in some anti-dandruff shampoos in the form selenium sulfide.
9. smelly when combined in organoselenium compounds of the form RSeH
10. used in some photocells because it has an allotrope that is a semiconductor, conducting electricity better in the light than in the dark.