1. 1. An electron has a __________ charge. Negative

2. 2. Protons have a __________ charge. positive

3. 3. Neutrons have a _________ charge. neutral

4. 4. Where is most of the mass found in an atom? nucleus

5. 5. What subatomic particles are found in the nucleus of an atom? Protons & neutrons

6. 6. Where are electrons likely to be found in an atom? Electron cloud

7. 7. Most of atom is __________ space where electrons are found. empty

8. 8. The periodic table organized elements by Atomic number

9. 9. The atomic number is the number of protons

10. 10. Elements in which group are poor conductors of heat and electricity? nonmetals

11. 11. What are isotopes? Atoms of the same element that have different numbers of neutrons.

12. 12. What is mass number? The sum of the number of protons and neutrons in an atom.

13. 13. What is an element? Pure substance that cannot be broken down into any simpler substances.

14. 14. The periodic table is mostly made of _________. metals

15. 15. How do you get the mass number? Round the average atomic mass to the nearest whole number.

16. 16. What determines an element’s identity? protons

17. 17. Which part of the atom is shared, gained, or lost when forming a chemical bond? electrons

18. 18. What is the atomic number of potassium? 19

19. 19. What is the atomic mass of Calcium? 40.08

20. 20. What is the mass number of iron? 56

21. 21. How many protons does Silicon have? 14

22. 22. How many neutrons does Argon have? 22

23. 23. How many electrons does Phosphorus have? 15

24. 24. A small particle that makes up matter is called ___________. an atom

25. 25. What are valence electrons? Electrons in the outermost energy level