1. Rounding Summary Fill in zeros where you have estimated Round to tens:
Whole numbers
Decimal Numbers
Fill in zeros where you have estimated
Round to tens:
756.09
760.
Drop all numbers that you have estimated
Round to tenths:
756.09
756.1

2. Rounding Practice Quiz- Quiz- Trade
You each get a card. When you are not paired up your hand is up.
Move around and pair up.
You will answer each question
Trade Cards.

3. What’s in that beam? J.J. Thomson, 1897
Cathode Ray Tube Experiments to measure the charge to mass ratio of the beam.
Particles in beam travel farther than hydrogen atoms.
The particles are 1000 times smaller than hydrogen atoms.

4. Thomson’s Model of the Atom 1897
Uniform base of positive charge with negative charges mixed within (electrons)

5. Ernest Rutherford, 1911
Gold Foil Experiment

6. What’s the pudding? 1911 Ernest Rutherford’s Gold Foil Experiment
Determined that the atom is mostly empty space
Nucleus is a tiny, dense positive region
Contains all of an atom’s mass
Later concluded that nucleus contains positive units (protons)

7. James Chadwick, 1932
After being released as a prisoner of WWI, Chadwick focused on radioactivity
Noticed discrepancies in the proton number and mass number
Used radioactive experiments to determine the neutral atom that has the mass of a proton (neutron)

8. Find Someone Who…
You will ask someone if they know the definition of the words in the left column
You will write their definition down
You will write their name
Once your done come back inside and glue on top half of pg 12

9. Atom Boards Open up your boards Let’s make a key Red= Protons
Blue= Electrons
Clear= Neutrons

10. Build me an atom of Oxygen
How many proton’s did you put in?
How many electrons did you put in?
How many neutrons did you put in?
Atomic number= number of protons- determines element identity
Mass number= protons + neutrons

11. Isotopes-atoms of one element that have different mass number
Isotopes change the number of ________
Build me an oxygen-18 atom
What does 18 represent?
Hyphen notation: element name – mass #

12. Mass # Practice Element Symbol Atomic # Mass # # of Protons
# of Neutrons
#of Electrons
Oxygen-16 16 Ru 58 26 56 23

13. Think it through
On the left page bottom half page

15. Ions- particles that carry a charge
Adding electrons creates an ANION- negatively charged atom
Removing electrons creates a CATION- positively charged atom