Lesson Plan: Grade 9 Science Unit Title: Atoms and Elements Lesson Title: Drawing Bohr atomic models– Lesson S1-2-05

Hydrogen Bohr Model

Bohr Model

• 3 electron orbits (shells)

• 1st shell; two electrons

• 2nd shell; eight electrons

• 3rd shell; eight electrons

1 Electron Shell

Helium

2 Electron Shells

Neon

3 Electron Shells

Chlorine

Electron Shells

• 1st then 2nd then 3rd

• Order of filling shells

• The exact position of electrons within the shell cannot be determined

Oxygen Bohr Model

• Atomic Number = 8

• Atomic Mass # = 16

• Protons = 8

• Neutrons = 16 – 8 = 8

• Electrons = 8

• 1st shell = 2

• 2nd shell = 6

Fluorine Bohr Model

• Atomic Number = 9

• Atomic Mass # = 19

• Protons = 9

• Neutrons = 19 – 9 = 10

• Electrons = 9

• 1st shell = 2

• 2nd shell = 7

Neon Bohr Model

• Atomic Number = 10

• Atomic Mass # = 20

• Protons = 10

• Neutrons = 20 – 10 = 10

• Electrons = 10

• 1st shell = 2

• 2nd shell = 8 • Full outer shell

Sodium Bohr Model

• Atomic Number = 11

• Atomic Mass # = 23

• Protons = 11

• Neutrons = 23 – 11 = 12

• Electrons = 11

• 1st shell = 2

• 2nd shell = 8

• 3rd shell = 1

Magnesium Bohr Model

• Atomic Number = 12

• Atomic Mass # = 24

• Protons = 12

• Neutrons = 24 – 12 = 12

• Electrons = 12

• 1st shell = 2

• 2nd shell = 8

• 3rd shell = 2

Helium

Boron

Chlorine

Assignment

• Complete Bohr-Rutherford Diagram of the first 20 elements

• Only do first 18, ignore K and Ca