chemistry vocab

3. any element in group 2 of the periodic table
5. any of the set of metallic elements in groups 4-12 of the periodic table
8. samples of a pure compound always contain the same elements
12. molecules composed only of two metals
17. a table of chemical elements arranged in order of atomic number
18. a positively charged elementary that is a fundamental constituent of all atomic nuclei
19. a positively charged ion
21. any of the gases in group O (18) of the periodic table

1. any of the elements in group ia 1 of the periodic table
2. theory that matter consists of of invisible particles called atoms
4. the number of positive charges of protons in the nucleus of an atom of a given element
6. an atom or molecule with a net electric charge due to the loss or gain of one or more electrons
7. an ionic species having a negative charge
9. a representation of a substance using symbols for its constituent elements
10. an element whose properties are intermediate between metals and solid non metals
11. any of two or more forms of a chemical element
13. an ionic bond is a chemical link between two atoms caused by an electrostatic force
14. the integer number nearest in value to the atomic weight of an atom and equal to the number of nucleons
15. an elementary particle that is a fundamental constituent of matter
16. element in group 17 of the periodic table
20. a fundamental group of atoms in a molecule serving as a base