It DOES Matter

4. the smallest unit of matter that retains all of the chemical properties of an element.
6. substances consisting of atoms that all have the same number of protons - (the same atomic number).
8. where electrons spend most of their time in sometimes-complex-shaped regions of space around the nucleus.
9. an expression that shows the number and types of atoms joined in a compound. (CO2 = Carbon Dioxide)
12. a table of the chemical elements arranged in order of atomic number, usually in rows.
14. anything that occupies space and has mass. It is made up of substances called elements.
16. when energy is absorbed from the surroundings in the form of heat.
18. a covalent bond where electrons are shared unequally.
20. the substances produced at the end of the reaction
21. pair of shared electrons between two atoms.
22. control center of a cell

1. occur when chemical bonds between atoms are formed or broken.
2. the internal make-up of the object (molecules) stays the same, even after the change — only its form changes.
3. a number written to the right and below of the chemical symbol. (CO2)
5. a group of atoms held together by a covalent bond.
7. uncharged/neutral particles
8. when energy is released from the system into the surroundings.
10. the area outside an atom's nucleus where electrons exist.
11. the substances that go into a chemical reaction
13. the force of attraction between positive and negative ions.
15. negatively charged particles
17. substances formed when two or more chemical elements are chemically bonded together.
19. positively charged particles