Teaching Sequence: Basic Electric Units

Learning Unit: What is Electricity

The Composition of Matter (Atomic Model by N. Bohr)

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The atom is composed of the core and the atomic shell.

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The atomic core itself consists of two different elementary particles:

protons and neutrons. These are called nucleons.

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Protons are positively charged elementary particles.

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Neutrons are non-charged elementary particles, they are electrically neutral.

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In the atomic shell the so called electrons move around the core.

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Electrons are negatively charged elementary particles.

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The numbers of the charges of proton and electron are exactly the same, but with a different polarity. Therefore they neutralize each other.

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The entire atom is electrically neutral to the outside.

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To give you an example of the size correlations: if the atomic core were as big as a can of beans the shell would be as large as a football stadium.