Warm Up 9-3-151. Write an equation to solve for volume.2. Explain why regular coke sink and

diet coke float when placed in water3. Express 0.000 000 6988 in scientific

notation4. Water has a ratio of 2 hydrogen atoms to 1

oxygen atom. What law explain this?

HomeworkSept 4 – Element Project

Bring pennies

AgendaTest Unit 1Notes Unit 2-2Element Project & Notebook

Test Unit 1• Multiple choice #1-25• Free response #26-27

– No calculators

• Do not write on the test• Bubble your ID #, record your Version ID and

Name on the answer document

Unit 2-2Structure of Atoms

Thompson’s Experiment

• J.J. Thompson a physicist that created the CRT (cathode-ray tube)

• To study current

Thompson’s ExperimentCRT•cathode electrode has negative charge•anode has positive charge•Glowing beam come from the cathode end•Deflected by a magnet = beam has a charge

Thompson’s Experiment

The Electron•The CRT beam moved a paddle wheel•Electron consists of particles that have mass and a negative charge

-Read only: e- are negatively charged but atoms have no charge, therefore atoms must contain + charge to balance the charges

Thompson’s Experiment

• “Plum Pudding” atomic model

Rutherford’s Experiment• Rutherford conducted gold-foil experiments

and discovered the nucleus.

Gold-Foil Experiment

Rutherford’s Experiment

Only a positively charged particle could repel the positively charged alpha beam

The mass of this particle has to be larger than the incoming beam to deflect it

Most of the atom is empty space that’s why only some beams were deflected

Subatomic Particles• The nucleus is made up of protons and

neutrons

• Proton: has a positive charge

• Electron: has negative charge

• Neutron: no charge.

• A neutral atom has no net charge, means # of protons = # of electrons.

Current Atomic Model

• Changes to Dalton’s atomic theory

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Assignments

• Notes Summary• Turn in notebooks• Bring pennies