CROSSWORD PUZZLE

2. a particle of matter that uniquely defines a chemical element
4. discovered the electron and then went on to propose a model for the structure of the atom
6. change of a solid into a liquid when heat is applied
8. the space occupied within the boundaries of an object in three-dimensional space
10. the quantity of matter contained in an atom of an element
13. He discovered and named the atomic nucleus, the proton, the alpha particle, and the beta particle.
15. a negatively charged subatomic particle that can be either bound to an atom or free (not bound)
17. the process by which a liquid turns into a gas
19. the number of protons in each atom.

1. a subatomic particle found in the nucleus of every atom
3. The smallest particle of a substance that has all of the physical and chemical properties of that substance
5. introducing the atomic theory into chemistry and for his work on human optics
7. the arrangement of electrons in orbitals around an atomic nucleus
9. a coherent, typically large body of matter with no definite shape.
11. Atoms with the same number of protons but different numbers of neutrons
12. the process where water vapor becomes liquid
14. a subatomic particle found in the nucleus of every atom except that of simple hydrogen
16. the proscess to convert from a liquid to a solid by cold
18. the structure in a cell that contains the chromosomes