Chemistry Puzzle

2. any of a class of substances characterized by high electrical and thermal conductivity
4. the structure in a cell that contains the chromosomes
5. poor conductors of heat and electricity.
6. smallest particle of an element which can exist itself
10. any substance that has a defined composition.
11. a horizontal row of the periodic table
17. a representation of chemical elements using one or two letters.
18. a subatomic particle with a positive electrical charge.
19. mass of a unit volume of a material substance.
20. ability to do work,
21. chemical substances made up of two or more elements that are chemically bound together in a fixed ratio.

1. quantitative measure of inertia, a fundamental property of all matter
3. the area around an atom's nucleus where electrons are most likely to be found.
5. subatomic particles found inside the nucleus of every atom.
7. The outermost shell or orbital of an atom
8. chemical element that exhibits some metal and some nonmetal properties.
9. occur when chemical bonds between atoms are formed or broken.
12. metal made by combining two or more metallic elements
13. the quantity of matter contained in an atom of an element.
14. a pure substance that cannot be broken down by chemical methods into simpler parts.
15. a column in the periodic table of the chemical elements
16. anything that takes up space and can be weighed.