3. What is the smallest unit of matter? An atom What is an atom made of? Subatomic particles protons (p + ) – positive charge neutrons (n) – no charge (neutral) electrons (e - ) – negative charge

4. Atomic Structure + + - - Nucleus (center)

5. Another way to represent an atom

6. Reminder: Atoms are vibrating, energetic things! + ++

7. Let’s Look at the Periodic Table 6 C Carbon 12 Atomic Number Atomic Symbol Atomic Mass

8. Atomic Number 6 C Carbon 12 Atomic Number # of protons in an atom # of electrons in an atom # of protons = # of electrons

9. Overall, do atoms have a charge? No! For All Atoms: # of positive charges = # of negative charges

10. Atomic Mass 6 C Carbon 12 Atomic Mass 1 proton = 1 amu 1 neutron = 1 amu Atomic Mass = # protons + # neutrons Using only the periodic table, how can you figure out the number of neutrons in an atom?

11. Calculating # of Neutrons Atom: Lithium (Li) Atomic Number: _3_

12. Calculating # of Neutrons Atom: Lithium (Li) Atomic Number: _3_ How many protons does one lithium atom have? _____

13. Calculating # of Neutrons Atom: Lithium (Li) Atomic Number: _3_ How many protons does one lithium atom have? _3_

14. Calculating # of Neutrons Atom: Lithium (Li) Atomic Number: _3_ How many protons does one lithium atom have? _3_ Atomic Mass: ___

15. Calculating # of Neutrons Atom: Lithium (Li) Atomic Number: _3_ How many protons does one lithium atom have? _3_ Atomic Mass: _7_ How many neutrons does lithium have? ___

16. Calculating # of Neutrons Atom: Lithium (Li) Atomic Number: _3_ How many protons does one lithium atom have? _3_ Atomic Mass: _7_ How many neutrons does lithium have? _4_

17. Drawing Atoms: Lithium (Li) Energy Levels (Shells): Start from the inside and move out as you need to Level/Shell 1: holds up to 2 e - Level/Shell 2: holds up to 8 e - Level/Shell 3: holds up to 8 e - 3 p + 4n An electron (e-)

18. Drawing Atoms: Lithium (Li) Energy Levels (Shells): Start from the inside and move out as you need to Level/Shell 1: holds up to 2 e - Level/Shell 2: holds up to 8 e - Level/Shell 3: holds up to 8 e - 3 p + 4n

19. Lithium + ++ 3 p + 4n