Matter and Chemistry

2. A substance that cannot be broken down into simpler substances by chemical means
5. The electrons in an atom's outermost electron shell
8. one of the three subatomic particles that make up an atom
9. a mixture in which the composition is not uniform throughout the mixture
14. a subatomic particle with a positive electrical charge
15. equal to the number of protons in the nucleus of an atom or the number of electrons in an electrically neutral atom
16. the membrane-enclosed organelle within a cell that contains the chromosomes
18. the point at which materials changes from a solid to a liquid
19. neither solids nor gases
21. organizes all discovered chemical elements in rows (called periods) and columns (called groups) according to increasing atomic number
22. the total mass of particles of matter in an atom

1. a row of chemical elements
3. a negatively charged subatomic particle that can be either bound to an atom or free (not bound)
4. a substance that is in a gaseous, or vaporous, state of matter
6. a material formed by chemically bonding two or more chemical elements
7. solid, liquid, gas, and plasma
10. firm and stable in shape; not liquid or fluid
11. the temperature at which its vapor pressure is equal to the pressure of the gas above it
12. a group of elements that have certain similar properties and can form compounds with some similar properties
13. a mixture in which the composition is uniform throughout the mixture
17. capable of being dissolved in a liquid
18. two or more substances that are mixed together but not chemically combined and that may vary in proportion
20. a particle of matter that uniquely defines a chemical element