Page 198 - Science Course 1 (Book 1)

Mo6-L1: Key Concept Organizer

Directions: Each set of items includes one that is larger than the other. Circle the larger item in each set of
items.

1. atom neutron
2. quark neutron
3. nucleus atom
4. nucleus proton

5. electron cloud atom
6. electron nucleus
7. atom electron
8. proton atom

9. nucleus neutron
10. proton quark

Mo6-L1: Key Concept Check

Directions: Place the events in chronological order from earliest to most recent by writing a number 1
through 7 on the line before the statement that describes each event.

J.J. Thomson investigates the electrical charges of atoms.

Democritus challenges the popular idea that matter is made of fire, water, air, and earth.

Niels Bohr investigates the energy level of electrons.

Students of Ernest Rutherford conduct the gold foil experiment.

John Dalton finds evidence to support the theory that all matter is made of atoms that cannot be
divided, created, or destroyed.

Scientists discover that protons and neutrons are made of quarks.

James Chadwick discovers that in addition to protons, the nucleus also contains neutrons.
Directions: Answer each question on the lines provided.

8. Where are electrons found in the modern atomic model?

9. Do you think that the modern atomic model will change in the future? Explain.

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