Chapter 7: Completing the Model of the Atom

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Chapter 7 Completing the Model of the Atom
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Class Activity (there is no BW)

• Send 1 student from your team to pick up enough
  white boards and markers for each person. 1 paper
  towel per team
• Draw a Bohr model for the element I assign to
  you.

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Class Activity (there is no BW)

• 2. Now, find all other students with the same
  number of occupied energy levels.
• Starting with Hydrogens group, stand together.
  Next, lithiums group, finally sodiums group.
• What do you notice?

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Class Activity (there is no BW)

• 3. Now, find all other students with the same
  number of valence.
• Starting with Hydrogens group, stand together.
  Then, Berylliums group, etc.
• Then, borons group, etc. What do students
  notice?

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What the Periodic Table Tells Us

• 1. Columns are called Groups or Families
• Main Group Elements are the tall ones!
• Groups 1 2, 13-18
• They follow the rules pretty well. Behavior is
  predictable.
• They tell us how many ______ the atoms of these
  elements have.
• Groups 12 Group tells you how many
• Groups 13-18- subtract 10 from the Group
• Transition Elements are in between Main Group
  Elements
• Groups 3-12
• Behavior is less predictable!
• Inner Transition Elements are at the bottom of
  the P. Table

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What the Periodic Table Tells Us

• 2. Rows are called Periods
• They tell us the location of the _______ in atoms
  of these elements.

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Use the P. Table to Make an e- Diagram for an
Element

• Ex Lithium
• Identify its Group 1
• Identify its Period 2
• Q So how many valence e-s does a lithium atom
  have? And where are they located?
• A 1 valence e- in the 2nd energy level

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Light Electromagnetic Spectrum

• Energy can travel in waves.
• There are high energy and low energy waves.
• The ones we can see are called the visible
  spectrum. ROY G BIV
• Red is the low energy end violet is the high
  energy end.

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Movement of e-s

• e-s can jump to higher energy levels if they
  absorb energy.
• They cant keep the energy so they lose it and
  fall back to lower levels.
• When they do this, they release the energy they
  absorbed in the form of light.

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Movement of e-s, cont.

• When e-s absorb energy, they do so in certain
  amounts. (They jump specific distances.)
• When they release energy, they do so in certain
  amounts. (They fall specific distances.) And
  they release light that has that amount of
  energy.
• Question if e-s fall a long distance, they
  release a lot of energy. What is the color that
  is likely to be released? (red end or purple end
  of spectrum?)

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Emission Spectrum

• Def Each element has a characteristic set of
  colors that are given off when its e-s fall
  back.
• You can identify an element by its emission
  spectrum!
• Emission spectrum of hydrogen

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Emission Spectrum (cont.)

• See Fig 7.4 on p 235
• H has 4 spectral lines (4 colored lines)
• Mercury (Hg) has 11 lines!
• Ne has 20 lines!
• Problem there are more lines than you would
  expect if there are only a few energy levels.
• Hypothesis There must be many sublevels in an
  energy level

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Electron Sublevels

• Each electron has an address, where it can be
  considered to be located in the atom.
• Main energy level hotel
• Sublevel floor
• Orbital room
• Regions of space outside the nucleus
• All orbitals in a sublevel have the same energy
• 2 electrons max can fit in an orbital

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Sublevels in Atoms
Main energy level Types of sublevels of orbitals of electrons
1 s 1
2 s p 1 3 (4 total)
3 s p d 1 3 5 (9 total)
4-7 s p d f 1 3 5 7 (16 total)

• See Fig 7.5 on p 235

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Orbitals

• s orbitals are spherical
• There is only 1 orbital
• p orbitals are dumbbell shaped
• There are 3 orbitals, all with energy
• Each is oriented on either x, y, or z axis
• They overlap
• d orbitals have varying shapes
• There are 5 orbitals, all with energy
• f orbitals have varying shapes
• There are 7 orbitals, all with energy

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Electron Configurations

• Electrons are always arranged in the most stable
  (lowest energy) way
• This is calledelectron configuration

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Section 2 The Periodic Table Atomic Structure

• Shape of p. table is based on the order in which
  sublevels are filled
• REGIONS OF THE P. TABLE (see p 244 of book)
• s REGION (block) - Groups 1 2
• p REGION (block) - Groups 13-18
• d REGION (block)- Groups 3-12 (Transition
  Elements)
• f REGION (block)- (Inner Transition Elements)

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List sublevels from lowest to highest energy
level (Using P.Table)

• 1. Always start with Period 1-go from L to R.
• 2. Go to Period 2-from L to R
• 3. Go to Period 3- from L to R
• 4. Continue 4-7 periods, L to R until you have
  completed the P. Table.
• Exception elements in d block are 1 main E.L
  lower than the period where they are located
• Exception elements in f block are 2 main E.L.s
  lower than the period in which they are located

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Correct Order of Sublevels (lowest to highest
energy)

• 1s, 2s, 2p, 3s, 3p, 4s, 3d, 4p, 5s, 4d, 5p, 6s,
  4f, 5d, 6p, 7s, 5f, 6d, 7p

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Why Exceptions w/d f block elements?

• When you get to the higher main E.L.s, the
  sublevels begin to overlap.

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E- configurations

• Use the P. Table to write the sublevels in
  increasing order, as previously instructed.
• Add a superscript next to each sublevel that
  shows how many e-s are in the sublevel
• Ex Oxygen 1s22s22p4

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Valence e-s

• Valence e-s are the electrons in the highest
  occupied main energy level.
• Identify the valence e-s by finding the biggest
  big number in your e- configuration.
• Ex Oxygen 1s22s22p4
• Question WHAT IS THE BIGGEST BIG NUMBER YOU
  SEE? WHAT ARE THE VALENCE ELECTRONS?

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Noble Gas Notation

• Short-cut way of showing e- configuration
• A Noble Gas is a Group 18 element.
• Identify the noble gas in the period above your
  element of interest. Write this symbol in
  brackets.
• Write the e- configuration for any additional e-s
  that your element of interest has, but the noble
  gas doesnt have.
• Ex Nitrogen 1s22s22p5 becomes He 2s22p5

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Practice Noble Gas Notation

• Tungsten (W)
• E- configuration
• Noble Gas configuration

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Arrow Orbital Diagram-Used to show e-
configuration.

• SYMBOLS
• A box represents an orbital
• Label each box with the sublevel 1s 2s 2p
  2p 2p
• An arrow represents an electron
• 2 arrows (e-s) in the same orbital face opposite
  directions.
• Example oxygen, see above

? ?
? ?
? ?
?
?
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Arrow Orbital Diagram-Used to show e-
configuration.

• INSTRUCTIONS
• Fill electrons from lowest to highest sublevel.
• Never place 2 e-s in the same orbital of a
  sublevel until you have placed one in each of the
  orbitals

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Arrow Orbital Diagram Practice
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Regions or Blocks of the P. Table