C1: Modern Atomic Theory

It is expected that students will write and interpret chemical symbols of elements and formulae of ionic compounds.

Students who have fully met the prescribed learning outcome are able to:

Describe the development of atomic theory,including
reference to Dalton, Rutherford, and Bohr

(Atomic theory powerpoint)

(Illustrated History of Atomic Theory)

Distinguish between atoms and molecules

Identify the three subatomic particles, their properties, and
their location within the atom (Standard model)

photo

RESOURCES:

Development of the chemical symbols and the Periodic Table

Construct model molecules with marshmallows, gumdrops and toothpicks

Life-sized models of atoms

The Particle Adventure (Activities/worksheets)

Matter!
This interactive module will introduce you to many of the basic properties of matter including atoms, ions, elements, molecules, and density.

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PLANNING FOR ASSESSMENT /ASSESSMENT STRATEGIES

Use an Anticipation Guide of five true and
false questions to begin the study of atomic
theory.

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Anticipation Guide
- The ancient Greeks first proposed
atoms. T/F
- An atom resembles a solid ball. T/F
- The first subatomic particle
discovered was the electron. T/F
- Atoms of an element can vary. T/F
- Atoms contain equal numbers of
positive and negative charges. T/F
• Present students with information on the
development of atomic theory and the
discovery of the three subatomic particles
(protons, neutrons and electrons),
including the contributions of Dalton,
Rutherford, and Bohr.

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Present students with information on the
development of atomic theory and the
discovery of the three subatomic particles
(protons, neutrons and electrons),
including the contributions of Dalton,
Rutherford, and Bohr.

Have students construct a timeline on atomic
theory. Look for evidence that students have
- included the major contributions of these
scientists
- described how understanding of the
components of the atom (protons, neutrons,
and electrons) has developed over time

• Have each student construct a chart in his or her
notebook containing information on the three
subatomic particles. Evaluate student charts
using the following template (italics indicates
the student response).

............................

                 Charge     Location     Relative    Symbol

_____________________________Mass      ________
Proton           +           Nucleus       1              p       
Neutron         0           Nucleus       1              n       
Electron         -           Outside    1/1800        e
                                    the
___________________Nucleus__________________

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Using molecular models to represent
atoms, have students combine these to
represent molecules. As an example, use a
black ball with four holes to represent a
carbon atom and attach four yellow balls to
represent hydrogen atoms, forming the
compound methane. Other molecules could
include water, hydrogen peroxide,
ammonia, carbon dioxide, and methanol.

Have students record (draw) the resulting
molecules. An accurate drawing would show
the correct number of atoms arranged with the
correct number of attachments (bonds).

Using the drawings of molecules above as
examples, have students determine a definition
of an atom and a molecule.