1. Warm up (10/25 and 26) Lab 5 in your lab books on your desk!
Write on board up here – what were your team’s results and method for Lab 5?

2. Lab 5 Results and Methods?
Percent Error =
Calculate percent error at the end of your calcs (in proper LABEL/SHOW format!)
Which method was “best”? Why?
42,000 atoms thick (Italian aluminum foil)
150,000 atoms thick (US aluminum foil)

3. Atomic Theories Mini-Lecture
Let’s draw pictures in our notes!
Great video recap
Also Chapter in your textbook
Tonight in your book read and add any notes you need

4. 1808 – John Dalton

5. Dalton (1808)
Atoms are tiny, hard spheres that are indivisible (nothing is smaller) and indestructible

6. Dalton
“We might as well attempt to introduce a new planet into the solar system, or to annihilate one already in existence, as to create or destroy a particle of hydrogen.”
John Dalton (1808)

7. Dalton thought that atoms were tiny, hard spheres
Dalton’s Laws (1808)
Each element is made up of tiny particles called atoms.
The atoms of a given element are identical; the atoms of different elements are different in some fundamental way or ways.
Dalton thought that atoms were tiny, hard spheres

8. Dalton’s Laws (1808) Atoms are unchangeable and indestructible.
Chemical compounds are formed when atoms combine with each other.
Chemical reactions involve reorganization of the atoms - changes in the way they are bound together.
Atoms are unchangeable and indestructible.

9. J.J. Thomson ( )

10. Called “plum pudding model”
J.J. Thomson ( )
Cathode Ray Tubes: corpuscles (electrons)
Called “plum pudding model”

11. J.J. Thomson ( )
There are particles INSIDE the atom that have negative charge (electron)
Electrons are in a “pudding” of positive charge
Explains their neutral charge overall

12. Application: CRTs Where do we see CRTs everyday?
Copper coils create a magnetic field so that the beam can be bent (steering coils) and your whole TV screen can be “painted”!

13. Ernest Rutherford (1911)

14. Ernest Rutherford (1911)
Tested Thomson’s plum-pudding model with gold foil
*Demo

15. Ernest Rutherford (1911)
Positive charge is CONCENTRATED in the middle of the atom
Most of the atom is EMPTY SPACE

16. Just how tiny is the nucleus?

17. Guess what?!
NONE of these models are currently thought to be the best description of the atom

18. SO WHAT? Science is always changing!!
There are TONS of things we still don’t understand – the science world needs YOU!
Science isn’t easy.

19. Which models can we identify now?

20. Recap: Which scientist “discovered” which model?
Atom with a positive center (nucleus)
Atoms are tiny spheres that make up all matter
Electrons (negative “charge”) exist

21. How’d we do?
Average = 71%

22. Test Corrections Time! (20 min)
On a separate piece of paper – correct all MC and written questions you missed
SHOW ALL WORK!
DO NOT TAKE PICTURES OR LEAVE ROOM WITH THE TEST - EVER
Do this ON YOUR OWN – learn from your mistakes! Make sure you understand!
This is an assignment in the test category – so it will help your grade IF you finish it!

23. Test Corrections!
Staple your corrections to the top of the test and turn into the inbox when done.
Finish up at lunch today, Th, or F if you don’t get done
Write “NEED MORE TIME” if you are not finished it is on you to come in and finish!

24. The Gas Problem – toughest question on the test!
Let’s look at it together!

25. If time: Pompeii Article!

26. Homework Day 2!
Read/Notes on pages in your textbook at home to make sure you’ve got the basics about atomic theory. Taking notes on your reading is always a great idea!
Come in at lunch Th or Fri to finish test corrections if not already done!