Elements

4. essential for healthy bones and teeth
6. basic unit for organic molecules
7. a very common element that causes rust to happen
9. most simple and most abundant element in the universe
11. most abundant metal in the earth's crust
12. ancient Egyptians used a sulﬁde compound of this element as eyeliner
16. its name was derived from the Greek word for “new”
17. most expensive substance in the world
19. sometimes confused with a synthetic rubber used for oven mitts and medical implants
20. alloyed with copper to make bronze

1. compounds in onions that can make you cry contain this element
2. discovered eight years after the discovery of the seventh planet from the Sun
3. when mixed with chlorine, it is transformed into something we eat everyday
5. poisoning from this element causes brain damage
8. most reactive nonmetal
10. named for the most famous scientist of the 20th century
13. key ingredient in ﬁreworks and explosives
14. used to kill bacteria in most public water supplies in the U.S.
15. a metal which melts on palm of the hand, due to its low melting point
18. rarest element on Earth