Bohr Models

Electrons and
Bohr Models

• Atoms interact with each other through their electrons.

• Chemical bonds involve only electrons, so electrons determine how atoms combine into compounds.

• Danish physicist Neils Bohr (1885–1962) proposed the concept of energy levels.

Electrons

• Electrons further away from the nucleus have more energy and electrons closer to the nucleus have less energy.

• The energy of an electron must match one of the energy levels in the atom.

• Each energy level can hold only a certain number of electrons, and no more.

• As electrons are added to an atom, they settle into the lowest unfilled energy level.

Multiple Choice

Electrons have ____ energy when they are farther away from the nucleus.

• More

• Less

In the Bohr model of the atom, the first energy level can accept up to 2 electrons. The second and third energy levels hold up to 8 electrons each. The fourth and fifth energy levels hold up to 18 electrons each.

Energy Levels

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Match

Match the following

• 2 electrons

• 8 electrons

• 8 electrons

• 18 electrons

First energy level

Second Energy Level

Third Energy Level

Fourth Energy Level

• First energy level

• Second Energy Level

• Third Energy Level

• Fourth Energy Level

Draw

Draw where the electrons for Carbon would be. (Carbon has an atomic number of 6)

Draw

Draw where the electrons for Aluminum would be. (Aluminum has an atomic number of 13)

Multiple Choice

How many neutrons does Beryllium have?

• 4

• 5

• 7

• 9

The electrons in the outermost energy level are called VALENCE ELECTRONS.

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These electrons interact with different atoms.

Valence Electrons

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Multiple Choice

The electrons in the outermost energy level of an atom are called...

• core electrons
• valence electrons
• inner electrons
• subvalence electrons

Math Response

How many valence electrons does Carbon have?

Type answer here

Correct Answer: 4

Deg^°

Rad

Math Response

How many valence electrons does Calcium have?

Type answer here

Correct Answer: 2

Deg^°

Rad

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