1. Atomic Structure OVERVIEW “Normal” Atoms Ions Isotopes

2. “Unseeable” Atoms What we know about atoms is based on “indirect” evidence. So, we really have “models” of atoms that may not be exactly right. BUT! Scientists don’t guess! www.teachnet.ie Electron Nucleus

3. “Normal” Atoms Protons Neutrons Electrons Nucleus Number of protons is constant for each element

4. “Normal” Atoms Li 7 3 LITHIUM Atomic NUMBER = protons

5. “Normal” Atoms Lithium = PROTONS DETERMINE IDENTITY !

6. Ions Protons Neutrons Electrons Electrons usually equal protons

7. Ions Protons Neutrons Electrons Electrons can be added or removed (to form “ions”)

8. Ions Protons Neutrons Electrons ELECTRONS DETERMINE CHEMISTRY!

9. Isotopes Protons Neutrons Electrons Neutrons can vary

10. Isotopes Protons Neutrons Electrons Different “isotopes” have different number of neutrons

11. Isotopes Li 7 3 LITHIUM Atomic MASS = protons + neutrons

12. YLDOI: Are You Smarter Than a First Grader? 1 1 st PART 1: Sally has 11 nickels and dimes in her piggy bank. If 5 of them are nickels, how many dimes does she have?

13. YLDOI: Are You Smarter Than a First Grader? 1 1 st PART 2: How many neutrons does boron have? B BORON 5 11

14. YLDOI: Are You Smarter Than a First Grader? 1 1 st PART 3: How many neutrons does R.E.D. have? ?

15. Isotopes Protons Neutrons Electrons NEUTRONS DETERMINE STABILITY!

16. Atomic Review

17. Protons determine identity.

18. Atomic Review Protons determine identity. Electrons determine chemistry.

19. Atomic Review Protons determine identity. Electrons determine chemistry. … and neutrons determine stability.