Thursday, Oct. 31st:

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Thursday, Oct. 31st A Day (1 05
release)Friday, Nov. 1st B DayAgenda

• Homework Questions/Collect
• Finish Section 3.3 Electron Configuration
• Quantum numbers, Pauli exclusion principle,
  electron configuration, aufbau principle, Hunds
  rule
• Electron Configuration Movie/Worksheet
• Homework
• Electron Configuration Movie Worksheet

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Homework Questions/Problem

• Isotopes worksheet
• Atomic Number and Mass Number worksheet

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Quantum Numbers

• Quantum number a number that specifies the
  properties of electrons
• Each electron has 4 quantum numbers
• Principal quantum number, n
• The main energy level
• Angular momentum quantum number, l
• The shape of the orbital (s, p, d, f)
• Magnetic quantum number, m
• The orientation of the orbital around the nucleus
• Spin quantum number, ½ or -½ (??)

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Pauli Exclusion Principle

• Remember, each orbital can hold a maximum of 2
  electrons.
• In 1925 the German chemist Wolfgang Pauli
  established a rule is known as the Pauli
  exclusion principle.
• Pauli exclusion principle the principle that
  states that two particles of a certain class
  cannot be in the exact same energy state.
• In plain English no two electrons in the
• same atom can have the same four
• quantum numbers.

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Electron Configuration

• Electron configuration the arrangement of
  electrons in an atom.
• Like all systems in nature, electrons in atoms
  tend to assume arrangements that have the lowest
  possible energies.
• An electron configuration of an atom shows the
  lowest-energy arrangement of the electrons for
  the element.

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Shapes of s, p, and d Orbitals
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Each Orbital Can Hold a Maximum of 2 Electrons

• There is only 1 s orbital for each main energy
  level. The s orbital can only hold 2 electrons.
• There are 3 p orbitals for each main energy
  level. The p orbitals can hold 2 electrons each
  for a total of 6.
• There are 5 d orbitals for each main energy
  level. The d orbitals can hold 2 electrons each
  for a total of 10.
• There are 7 f orbitals for each main energy
  level. The f orbitals can hold 2 electrons each
  for a total of 14.

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An Electron Occupies the Lowest Energy Level
Available

• Aufbau principle the principle that states that
  the structure of each successive element is
  obtained by adding one proton to the nucleus of
  the atom and one electron to the lowest-energy
  orbital that is available.
• In plain English electrons occupy orbitals that
  have the lowest energy first.

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Orbital Filling Chart

• This diagrams shows how the energy of the
  orbitals can overlap.
• Because the 4s orbital has a lower energy than
  the 3d orbital, it will fill first.

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Hunds Rule

• Electron orbitals are filled according to Hunds
  Rule.
• Hunds rule the rule that states that for an
  atom in the ground state, the number of unpaired
  electrons is the maximum possible and these
  unpaired electrons have the same spin.
• In plain English all orbitals in a given
  energy level must have 1 electron each before any
  pairing occurs.
• Dont HOG electrons!

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Writing Electron Configurations

• There are 2 different ways that electron
  configurations can be represented
• With arrows
• ____ ____ ____ ____ ____
• 1s 2s 2p 2p 2p
• Each horizontal line represents an orbital.
• Each arrow represents an electron with a
  different spin.
• Which element do you think this this?

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Writing Electron Configurations

• With electron configuration notation
• 1s22s22p5
• The big numbers indicate the main energy level, n
  
• The letters indicate the orbital type.
• The superscripts show the number of electrons.
• Which element do you think this this?

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Electron Configuration Practice

• Use arrows to write the electron configuration
  for an atom of an element whose atomic number is
  8.
• Atomic Number of protons
• protons electrons 8
• Use the orbital filling chart to place the 8
  electrons in their proper orbitals.
• Remember, the s orbital can only hold 2 electrons
  and the 3 p orbitals can hold 2 electrons each
  for a total of 6.
• ____ ____ ____ ____ ____
• 1s 2s 2p 2p 2p

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Sample Problem C, pg. 98

• Use arrows AND electron configuration notation to
  write the electron configuration for an atom
  whose atomic number is 20.
• Atomic Number of protons
• protons electrons 20
• Use the orbital filling chart to place the 20
  electrons in their proper orbitals
• __ ____ ____ ____ ____ ____ ____ ____
  ____ ____
• 1s 2s 2p 2p 2p 3s
  3p 3p 3p 4s
• 1s22s2sp63s23p64s2
• 1s22s22p63s23p64s2

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Electron Configuration Practice

• Use arrows AND electron configuration notation to
  write the electron configuration for an atom that
  has 17 electrons.
• Use the orbital filling chart to place the 17
  electrons in their proper orbitals
• ____ ____ ____ ____ ____ ____ ____ ____
  ____
• 1s 2s 2p 2p 2p 3s
  3p 3p 3p
• 1s22s22p63s23p5

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Movie Writing Electron Configurations

• Welcome back Mr. Sweatervest!
• Follow along and complete the student examples as
  they are being discussed in the movie.
• The rest of the worksheet,
• front and back, is homework.

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Homework

• Complete the rest of the movie worksheet.
• Next time section 3.3 work day!
• Dont forget to set your clocks 1 hour BACK
  Saturday night
• (you get an extra hour of sleep!)