i:i understand the structure of matter. 1. what is a model and how do scientists use them? reality...

I:I Understand the structure of matter

1. What is a model and how do scientists use them?

• Reality is complex.• Study as a whole.• Make predictions.• Only a

representation.

2. How small is an atom?

a. The width of one hair is one million atoms.b. An atom is as small as a cell.c. You can see atoms through our classroom microscopes.

3. What do scientists use models for?

4. How are models limited in how they present information?

5. What did previous scientists do and what were their contributions to help develop the atomic theory and our current model of an atom.• ..

Scientists add to theory of atomDemocritus 450 BC

Aristotle 350 BC

Dalton 1800

Thomson 1897

Rutherford 1899

Bohr 1913

Uncuttable = ‘atomos’

Setback for 2000 years

Gas experiments showed that tiny particles combine.

Vacuum tube showed negative charges.

Gold Foil experiments found nucleus.

Fixed energy levels.

6. What is the electron cloud?

7. Where are the following located: • a. nucleus

• b. electrons• c. neutrons• d. protons

8. What is a periodic table?

9. Who is Dimitri Mendeleev & what did he do?

10. What is the difference between (a)molecules & (b)compounds?

Hydrogen H2

Oxygen 02

Nitrogen N2

Water H20

Carbon Dioxide C02

Methane CH4

11. What are the main properties of solid, liquid and gas?

(a) No definite shape, but definite volume.(b) No definite shape, no definite volume. (c) Definite shape, but definite volume.