Drawing Models of the Atom

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Drawing Models of the Atom

• The Bohr Model

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How do Scientists View the Atom Today?

• 2 models are most widely used
• The Bohr Model and the Electron Cloud Model

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• Both of these models explain how the electrons
  are arranged in the electron cloud.
• However, the Bohr Model is Much Easier to Draw
  and Visualize
• We will be drawing Bohr models today.

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The Bohr Model(Planetary Model)

• Electrons are located in specific orbitals
  (energy levels) Circles
• Only so many electrons will fit into each
  electron level.
• Levels are filled from the innermost working out.
  Fill inside circles first.

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How to do it

• Find number of electrons, protons neutrons from
  the atomic number and atomic mass.
• Draw a little circle for the nucleus and label
  with number of protons and neutrons.
• Draw larger circles for each energy level.
• Draw dots for each electron representing the
  electrons in each orbital on these circles.

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OK, now how do you to really do it?

• You use the periodic table
• Each period represents an electron level
• Each row is
• 1 circle
• Each square represents an electron

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Thus it is a Numbers Game

• The periods (rows) tell you how many circles
  (electron shells).
• The squares will tell you how many electrons on
  each orbital.

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• You will notice that each period has a certain
  number of squares
• This tells you how many electrons can fit in each
  period

• Energy Levels Max Electrons 1st 2
• 2nd 8
• 3rd 18
• 4th 32
• 5th 50
• 6th
• 7th

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Sodium Example

• Atomic number 11
• Atomic mass 23
• In period 3
• Thus number of electrons 11
• protons 11
• neutrons 12
• orbitals 3

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• Place a dot ( ) for each electron on the
  orbitals
• Sodium has
• 1st orbital 2 e-
• 2nd orbital 8 e-
• 3rd orbital 1 e-
• total 11e-

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Draw a Bohr Model of your atom model

• Atom Name
• Atom Number p
• Number of e-
• Number of n0
• Energy Levels Electrons 1st 2
• 2nd 8
• 3rd __
• 4th __
• 5th __

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• Note To Teacher
• Let the next slide run by itself to see the model
  of several atoms.

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A Few of the Atoms
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Now it is your Turn!

• Lets try it.
• Draw Kr in your
• Powerpoint notes.