How are the protons and electrons in atoms arranged? Super Models How are the protons and electrons in atoms arranged?

In your notebook Super Model, Part 2 Modeling atoms using math Rutherford’s model In your notebook

Reading, p. 172 Let’s go over the reading together Mathematical models How many dates per year your have How many cars per lifetime you crash Etc. Reading, p. 172

Scientific Notation A short-hand way of writing large numbers without writing all of the zeros.

The Distance From the Sun to the Earth 93,000,000

Step 1 93,000,000 = 9.3000000 Move decimal left Leave only one number in front of decimal 93,000,000 = 9.3000000

Step 2 Write number without zeros 93,000,000 = 9.3

Step 3 7 93,000,000 = 9.3 x 10 Count how many places you moved decimal Make that your power of ten 93,000,000 = 9.3 x 10 7

The power of ten is 7 because the decimal moved 7 places. 7 93,000,000 = 9.3 x 10 7

93,000,000 --- Standard Form 9.3 x 107 --- Scientific Notation

Practice Problem -----> -----> -----> -----> Write in scientific notation. Decide the power of ten. 98,500,000 = 9.85 x 10? 64,100,000,000 = 6.41 x 10? 279,000,000 = 2.79 x 10? 4,200,000 = 4.2 x 10? 9.85 x 107 -----> 6.41 x 1010 -----> 2.79 x 108 -----> -----> 4.2 x 106

More Practice Problems On these, decide where the decimal will be moved. 734,000,000 = ______ x 108 870,000,000,000 = ______x 1011 90,000,000,000 = _____ x 1010 Answers 3) 9 x 1010 7.34 x 108 2) 8.7 x 1011

Complete Practice Problems Write in scientific notation. 50,000 7,200,000 802,000,000,000 Answers 1) 5 x 104 2) 7.2 x 106 3) 8.02 x 1011

Scientific Notation to Standard Form Move the decimal to the right 3.4 x 105 in scientific notation 3.40000 --- move the decimal ---> 340,000 in standard form

Move the decimal to the right. Write in Standard Form Move the decimal to the right. 6.27 x 106 9.01 x 104 6,270,000 90,100

Worksheet Get ‘r’ dun! Super important skill for science

P&P p. 173 2. Modeling something in your life: Some translations: Think of a situation where math models help you plan Describe it in a sentence Translate the sentence into a model Some translations: “Makes” - “=“ “And” – “+” or “x” “Between all of us” or “Shared” - “/” P&P p. 173

P&P 173 3. Math time! D = Speed X Time A. Here’s the answer: 1.3 X 103m How did we get that? D = Speed X Time D = (3.0 X 107 m/s) X (4.2 X 10-5 s) D = 30000000 m/s X 0.000042 s D = 1300 m P&P 173

3. Continued: B. Do you think Rutherford made his lab that long? Why or why not? P&P 173

P&P 173 3. Continued Distance is Speed X Time Time = Distance/Speed C. Rutherford’s lab was 10 meters long (not the 1300 we talked about earlier). How long would it take for the alpha particles to move that distance? Distance is Speed X Time Time = Distance/Speed Speed = 3.0 X 107 m/s Distance = 10 meters P&P 173

P&P 178 3. Continued… D. How fast did the particle travel? (Speed = Distance/Time) 50 X 10-9 m 1 X 10-15 seconds P&P 178

P&P 178-179, Question 4 Goal: make a properly scaled model of an atom What would the volume of a model atom be if you have a nucleus the size of a grapefruit? Very difficult, but you need to take your time and do it Volume of grapefruit: P&P 178-179, Question 4

A: just giving you the diameter of an atom and a nucleus A: just giving you the diameter of an atom and a nucleus. You will need this. B, C: giving you formulas you will need D: the table you will use to figure out the volume of the model atom. E: Think about how… Ratio of volume of nucleus to the volume of atom is the same as volume of grapefruit to volume of the whole model Notice they give DIAMETER of atoms and nuclei when you need RADIUS; how are those related? Question 4

Is it ultimately possible for us to make a good model using a grapefruit? How far would we have to put the edge of the atom away from the nucleus (how big is the radius)? Does this mathematical model help you understand it all? Question 4