Matter: Ch. 3, Sec. 1 & 2

3. Negatively charged particles.
6. The top number of an element and it is the number of protons in the nucleus of that atom.
8. The positively charged center of an atom.
10. The small particle that makes up most types of matter.
13. The number of electrons that can be found in the lowest energy level near the nucleus.
14. Are atoms of the same element that have a different number of neutrons.
17. A man who did an experiment with gold foil to prove that atoms were mostly empty space.
18. Elements that have characteristics of metals and nonmetals.
19. Elements that are generally dull in appearance and not good conductors.
21. Is the weighted average mass of the isotopes of an element.

1. Matter is not created of destroyed, it only changes forms.
2. A positively charged particle.
4. Matter made of one type of atom.
5. The scientist who found that electrons in atoms are arranged according to energy levels.
7. A particle with no charge.
9. Is the number of protons plus the number of neutrons in a nucleus.
11. A man who developed the idea that matter was made of atoms.
12. The student of Ernest Rutherford who discovered particles with no charge.
15. Anything that has mass and takes up space.
16. An English scientist who used cathodes to prove that negative particles existed.
20. Elements that are generally shiny or metallic luster and are good conductors of heat and electricity.