Electrons in Atoms: Electron Configuration

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Electrons in Atoms Electron Configuration

• Chemistry
• EQs What is the relationship between matter and
  energy?
• How does the behavior of electrons affect the
  chemistry of atoms?

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GPS

• SC3 Students will use the modern atomic theory to
  explain the characteristics of atoms.b. Use the
  orbital configuration of neutral atoms to explain
  its effect on the atoms chemical properties.f.
  Relate light emission and the movement of
  electrons to element identification.

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Vocabulary

• Aufbau Principle
• Pauli Exclusion Principle
• Hunds Rule
• Electron Configuration
• Valance Electron
• Energy levels

• Lewis Structure
• Ground state
• Excited state
• Orbitals
• Quantum

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Excited Electrons
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Bohr Model of the Atom

• Bohrs Model electrons orbit the nucleus only
  orbits in certain energies are permitted.
• Ground State- lowest E level
• Excited State- Higher than ground state.
• The e- are raised to the next level, then release
  light when they return to ground state
• Must have enough E to raise to next level or
  wont happen.

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Bohr Model
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Bohr Model of the atom
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Electrons

• DeBroglie-
• Quantum Mechanics- light behaves as wave
  particles
• Visible objects (baseball) have ? too small to
  see, need very small object to detect ?
•  Heisenburg Uncertainty Principle- Cant know the
  position speed of electron at the same time

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Bohr Model ? Quantum Model

• E- do not fall towards nucleus
• E- reside in electron clouds called orbitals

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Electrons

• Energy levels- region around nucleus where e-
  likely to be found (electron density is high)
• Quantum- amount of energy for e- to jump levels
• Continuous- ramp, no units
• Quantitized- fixed levels, fixed units

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• Schrodinger- estimates the probability of e- to
  be in certain area electrons are like a fuzzy
  cloud, but more dense more likely to find e- 90
  of the time in a particular location
• Orbitals-Wave functions with corresponding
  densities (shape and energy)
• orbital is NOT the same as Bohrs orbit

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Electron configuration

• RowPeriodEnergy Level gt horizontal
• Column Group/ Familygt vertical
• Elements in the same family have the same of
  valence electrons share similar chemical
  properties.
• Valence electrons e- in to last energy level.
• Valence e- correspond w/ group (does not
  include transition elements)
• Group 1A 1 valence e-
• Group 2A 2 valence e-
• Group 3A (13) 3 valence e-
• Group 4A (14) 4 valence e-
• Group 5A (15) 5 valence e-
• Group 6A (16) 6 valence e-
• Group 7A (17) 7 valence e-
• Group 8A (18) 8 valence e- ? FULL SET STABLE

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Electron Configuration

• Tells the arrangement of electrons around the
  nucleus of an atom
• Written in ground state, which is the lowest
  energy most stable arrangement
• e- arrange from lowest to highest E level

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Electron configuration.

• Orbital the 3-D space around the nucleus that
  describes an electrons probable location.
• Energy Level (n) indicate the relative sizes
  energies of atomic orbitals.
• As n increases, the orbitals become larger, and
  the e- spends more time farther from the nucleus.
  
• n major energy levels n 1-7 correspond w/
  the 7 rows on the P.T.
• Sublevel energy levels contained w/in a energy
  level
• s, p, d, f

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Electron Configuration
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What shape are the orbitals?

• s and p Orbitals

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Electron Configuration

• Tells the arrangement of electrons around the
  nucleus of an atom
• Written in ground state, which is the lowest
  energy most stable arrangement
• Follows 3 rules
• Aufbau Principle
• Pauli Exclusion Principle
• Hunds Rule

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Aufbau Principle

• Each electron will occupy the lowest available
  energy level 1st, then higher energy levels.

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Pauli Exclusion Principle

• A maximum of 2 electrons with opposite spins
• can fit in an orbital (No more than 2 e-
  can occupy orbitals).
• e- in the same orbital must have opposite spin
  (repulsion)
• Show each orbital w/ its own box
• One is spinning clockwise the other is counter
  clockwise, Show this with one arrow going up
  one pointing down.
• NOT

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? ?
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Hunds Rule

• Single electrons with the same spin must occupy
  each equal energy level before additional
  electrons with opposite spins can be added
• e- enter orbitals singularly, then pair up
• Example when filling the p sublevel with 4e-,
  each box gets 1 before doubling up one box
• NOT

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Electron Configuration-

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• Using the PT
• The principal quantum number , n period.
• There are 4 blocks (s, p, d, f)
• Noble gasesfull s p level making them inert
  (stable).
• Alkali Metals- s1
• Alkaline Earth Metals- s2
• Transition Elements- d1-d10
• Inner Transition Elements- f1-f14

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Electron Fill Sequence
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Electron Configuration
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Electron Sequence Model
Follow the yellow brick road
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Electron Configuration

• Examples
• F 1s22s22p5
• Cl 1s22s22p63s23p5
• Al 1s22s22p63s23p1
• Br 1s22s22p63s23p64s23d104p5

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Orbital DiagramsUses boxes to represent orbitals
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Noble Gas Notation

• Simplified version of writing e- configurations
• Noble gas is placed in brackets

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Noble Gas Shortcut

• When doing configurations for large numbers of
  electrons, we can take a short cut using noble
  gases. (yay!)
• Example, lets try Sulfur (16 electrons)
• The noble gas that comes before Sulfur is Neon
• Noble gas is placed in brackets
• Place noble gas in bracket to represent the e-
  configuration up to that noble gas.
• Write the rest of the e- config. for that
  element.
• So we could shortcut by writing Ne 3s2 3p4
• Now you try Manganese and Strontium

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Electron Configuration and Orbital Notation
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Valence Electrons

• e- in the outer most energy level that determines
  chemical properties
• Lithium 1s2 2s1
• Bromine 1s2 2s2 2p6 3s2 3p6 4s2 3d10 4p5
• Aluminum Ne 3s2 3p1
• Family Number
• VE are the electrons
• available to form chemical
• bonds w/ other elements.

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Lewis Dot Structure Electron Dot

• Chemical symbol valence electrons of atom
• Valuable in showing how atoms share electrons in
  covalent bonds
• We can draw Lewis structures for every element
  using valence electrons
• Count the of valence electron, then arrange
  then around the symbol for the atom one at a
  time up to 8 electrons.
• Arrange 1/ side around the symbol, then couple up
  if more than 4 electrons.

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Lewis Dot