ELEMENTS

6. Horizontal arrangement of elements in the periodic table
8. Sanskrit word that means "first"
10. classification of elements that exhibit properties of both metals and nonmetals
11. first word of the collective name for the elements in Group 8A
13. elements found in the longer columns of the periodic table; also called A groups
15. elements found in the shorter columns of the periodic table; also called B groups
17. English chemist who proposed the law of octaves
19. term used for the electrons in the outermost shell of the atom
20. vertical arrangements of elements in the periodic table
21. classification of elements that tend to form cations

1. number of electrons in the outermost shell of a carbon atom
2. first element in alkali metals
3. collective name for the elements with atomic numbers 57-81
4. collective name for the elements in Group 7A
5. Russian chemist who proposed the arrangement of elements based on increasing atomic masses
7. an atom or a group of atoms that has a net positive or negative charge
9. word that describes the repeating chemical properties of elements
12. Element that belongs to Group 3A, Period 2
14. particles found in the nucleus aside from neutrons
16. first element in group 5A
18. another term for the horizontal arrangement of elements in the periodic table