Science 9 - Bohr Diagrams

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Bohr Diagrams
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The Atom

• Smallest particles of matter, everything is made
  out of atoms
• Atoms are made of subatomic particles

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Atomic Structure(see handout Atomic Structure
Periodic Table )

• PROTONS NEUTRONS
• Found in the nucleus
• Both have mass
• Protons carry an electrical charge
• ELECTRONS
• Have negligible mass
• Carry an electrical charge
• Orbit the nucleus within electron shells

Electron Shells
PROTONS
NUCLEUS
NEUTRONS
ELECTRONS
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Atomic Structure

• Properties of Subatomic Particles

PARTICLE RELATIVE MASS RELATIVE CHARGE
Neutrons 1 0
Protons 1 1
Electrons Negligible -1
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Reviewing Atomic Structure
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Bohr Diagrams

• A method of drawing atoms
• Based on planetary model of solar system
• Electrons circle nucleus in orbits (electron
  shells)
• You draw atoms based on the information provided
  by the periodic table

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Orbits in Bohr Diagrams

• Orbits or Energy Levels in Bohr Diagrams can hold
  a maximum number of electrons

ENERGY SHELL NAME OF SHELL MAX of ELECTRONS HELD
1 K 2
2 L 8
3 M 8
4 N 18
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Orbits in Bohr Diagrams

• A electron shell / orbit is simply the area in
  which you find electrons
• Once you fill a shell you move to the next shell

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Bohr Diagrams
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A Real Atom
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Bohr Diagram of Helium
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Bohr Diagrams

• Now lets look at the steps to draw a Bohr
  diagram......

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Examples

• Lets complete examples of Bohr Diagrams for
• Carbon
• Fluorine
• Neon
• Magnesium

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Ex. 1 - Carbon
Ex. 1) How many protons, neutrons and electrons
are found in Carbon?

• ATOMIC MASS
• __ Protons __ Neutrons 12

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6
C

• ATOMIC NUMBER
• of Protons of Electrons
• Carbon has 6 protons
• Carbon has 6 electrons

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Ex. 1 - Carbon
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Ex. 2 - Fluorine
Ex. 2) How many protons, neutrons and electrons
are found in Fluorine?

• ATOMIC MASS
• __ Protons __ Neutrons 19

10
9
F

• ATOMIC NUMBER
• of Protons of Electrons
• Fluorine has 9 protons
• Fluorine has 9 electrons

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Ex. 2 - Fluorine
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Ex. 3 - Neon
Ex. 3) How many protons, neutrons and electrons
are found in Neon?

• ATOMIC MASS
• __ Protons __ Neutrons 20

10
10
Ne

• ATOMIC NUMBER
• of Protons of Electrons
• Neon has 10 protons
• Neon has 10 electrons

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Ex. 3 - Neon
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Ex. 4 - Magnesium
Ex. 3) How many protons, neutrons and electrons
are found in Magnesium?

• ATOMIC MASS
• __ Protons __ Neutrons 24

12
12
Mg

• ATOMIC NUMBER
• of Protons of Electrons
• Magnesium has 12 protons
• Magnesium has 12 electrons

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Ex. 4 - Magnesium