General Chemistry

3. rarest gas in the atmosphere
6. each of two or more different physical forms in which an element can exist.
7. its atomic mass is 20.1797 U
10. relating to or denoting chemical bonds formed by the sharing of electrons between atoms.
12. This is everything around you.
15. element whose atomic weight is 145
17. symbol for the element praseodymium
18. also known as quicksilver, element with the atomic number 80
19. symbol for the element Tin
20. element with the atomic number 69

1. is by far the most abundant element in the Earth's crust.
2. symbol for the element Cobalt
4. It is named after the American nuclear chemist Glenn T. Seaborg.
5. element with the atomic number 5
8. symbol for the element Oganesson
9. From Ancient Greek: κρυπτός, romanized: kryptos meaning "the hidden one"
11. is the smallest constituent unit of ordinary matter that constitutes a chemical element.
13. an atom or molecule that has gained or lost one or more of its valence electrons
14. element with the atomic number 39
16. symbol for the element actinium
21. symbol for lithium