chemistry vocabulary

3. any of the gases in group O (18) of the periodic table
5. samples of a pure compound always contain the same elements
7. a table of chemical elements arranged in order of atomic number
8. an elementary particle that is a fundamental constituent of matter
9. the integer number nearest in value to the atomic weight of an atom and equal to the number of nucleons
11. molecules composed only of two metals
13. any element in group 2 of the periodic table
17. a positively charged ion
18. any element in group 17 of the periodic table
19. an ionic species having a negative charge

1. an ionic bond is a chemical link between two atoms caused by an electrostatic force
2. theory that matter consists of of invisible particles called atoms
4. any of two or more forms of a chemical element
6. a fundamental group of atoms in a molecule serving as a base
7. a positively charged elementary that is a fundamental constituent of all atomic nuclei
10. an element whose properties are intermediate between metals and solid non metals
12. a representation of a substance using symbols for its constituent elements
13. any of the elements in group ia 1 of the periodic table
14. the number of positive charges of protons in the nucleus of an atom of a given element
15. an atom or molecule with a net electric charge due to the loss or gain of one or more electrons
16. any of the set of metallic elements in groups 4-12 of the periodic table