THE ELECTRON

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THE ELECTRON

• CHAPTER 5

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Chapter 5 Overview

• Chapter 5 focuses on the electrons within atoms
  for two reasons
• Electrons account for the elements reactivity or
  personality
• Electrons are the first things that surrounding
  atoms encounter when they come upon the atom

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• 5.1 Light Quantized Energy
• Electromagnetic Radiation
• -A form of energy that exhibits wavelike
  behavior as it
• travels through space.
• -Visible light
• -Microwave
• -X-rays
• -Radio waves
• -Television waves
• All electromagnetic waves are standing waves that
  have frequency, wavelength, and amplitude

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• Waves
• ? (wavelength)
• -the distance between crests or troughs
• V (frequency)
• -the number of waves that pass a point every
  second measured in Hertz
• (Hz)
• A (amplitude)
• -The highest point or the lowest point from the
  equilibrium line of a wave
• C (speed of a wave)
• -The speed wavelength x frequency
• T (period of the wave)
• -complete cycle of the wave crest-trough-crest
• Speed of Electromagnetic Magnetic Radiation
• -3.00 x 108 m/s

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Wavelength vs. Frequency

• Wavelength and frequency have an inverse
  relationship

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Electromagnetic Spectrum
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• Plancks Theory
• There is a specific amount of energy that matter
  can gain or lose. This small amount of energy is
  a quanta.
• Quantum-is the minimum amount of energy that can
  be gained or lost by an atom.
• Quantum-fixed amount
• Mathematical formula for quantum energy (E v x
  h)
• E energy
• v frequency
• h Plancks constant (6.626 x 10-34 J per second)

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• Einstein Planck
• Einstein used photons to explain the
  photoelectric effect.
• Einstein proposed that the energy of a photon of
  light must have a certain minimum value to cause
  the ejection of a photoelectron.

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Emission Line Spectra

• Atomic Emission Spectrum/Line Spectrum
• contains only certain colors, or wavelengths
• All elements emit light when they are vaporized
  in an intense flame or when electricity passes
  through their gaseous state.
• Atoms absorb then release energy in the form of
  light.
• Every element emits light containing only certain
  wavelengths (line spectrum, color)

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5.2 Quantum Theory and the Atom

• Neils Bohr Atomic Model
• Described the atom as electrons moving around the
  nucleus in well defined orbits .
• The smaller the orbit, the lower the energy.
• The larger the orbit, the higher the energy.
• -n1, n2, n3, n4
• Ground State
• the lowest allowable energy state of an atom

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Excited Electrons

• When electrons in the ground state gain energy,
  they can move a greater distance from the nucleus
  to an excited state.
• When the electrons lose the gained energy they
  fall back to the ground state and release the
  energy in the form of radiation.

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Electron Excitation

• Electrons are not stuck in ONE principle energy
  level
• If energy is added to the atom, the electrons can
  jump to higher energy levels
• Ground State
• Resting state
• Excited State
• State where electron goes when energy is added
• Atomic Spectrum (energy released)
• Wavelength
• Frequency
• ROYGBIV

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Broglie Heinsberg

• Louis de Broglie
• predicted all moving particles have wave
  characteristics.
• Heisenberg Uncertainty Principle
• it is impossible to know precisely the velocity
  and position of a particle at same time.

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Schrödinger

• Quantum Mechanical Model of the Atom
• -An atomic model in which the electrons are
  treated as waves.
• Atomic Orbital
• -a three dimensional region around the nucleus

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• Principle Energy Levels
• Energy levels of an atom
• -n specifies the atoms major energy levels
• -The principal energy levels are assigned a
• number from 1-7
• -The principal energy levels contain energy
• sublevels
• -These sublevels are called orbitals.

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n1 -principal energy level 1 -consists of 1
sublevel n2 -principal energy level
2 -consists of 2 sublevels n3 -principal
energy level 3 -consists of 3
sublevels n4 -principal energy level
4 -consists of 4 sublevels
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• Atomic Orbitals
• The orbital is a particular volume of space
  around the nucleus.
• Each atomic orbital is a three dimensional region
  around the nucleus.
• Each orbital describes the electrons probable
  location.
• -All Electrons occupy energy levels only no
  electrons between
• -All principal quantum numbers n 1, 2, 3, 4
• -All Communicates the distance from the nucleus
  and amount of
• energy
• -All Outermost electrons communicate the row on
  the periodic table

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• Principle Energy Levels
• Principal Energy Levels
• ( n 1 through 7 )
• Sublevels
• -( s. p. d. f )
• Orbitals
• -s 2 electrons
• -p 6 electrons
• -d 10 electrons
• -f 14 electrons

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• 5.3 Electron Configuration
• The arrangement of electrons in an atom.
• -s 1 orbital
• (maximum of 2 electrons )
• -p 3 orbitals
• (maximum of 6 electrons)
• -d 5 orbitals
• (maximum of 10 electrons)
• -f 7 orbitals
• (maximum of 14 electrons)

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Maximum Electrons

• Each energy level can only hold so many electrons
• Energy Level 1 (n1)
• MAXIMUM of 2 e-
• Energy Level 2 (n2)
• MAXIMUM of 8 e-
• Energy Level 3 (n3)
• MAXIMUM of 18 e-

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Stop Notes Part 1 Here

• Complete Sections 5.1-5.2 Review Worksheets

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Electron Configuration using the Periodic Table
Dandelion (yellow)
Purple
Spruce (green)
Fuschia
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Electron Arrangement

• Called ELECTRON CONFIGURATION
• A series of letters numbers giving specific
  information about every electron in an atom
• We will use the analogy of CHIEF HOTEL to
  describe Electron Configuration set-up and rules.

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CHIEF HOTELACCOMODATIONS

• Single Room (s)
• One bed
• Two guests maximum
• Spruce (green) in color
• Located on floors 1-7

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CHIEF HOTELACCOMODATIONS

• Prestige Room (p)
• Three beds
• Six guests maximum
• Purple in color
• Located on floors 2-7

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CHIEF HOTELACCOMODATIONS

• Deluxe Room (d)
• Five beds
• Ten guests maximum
• Dandelion (yellow) in color
• Located on floors 3-6

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CHIEF HOTELACCOMODATIONS

• Fabulous Room (f)
• Seven beds
• Fourteen guests maximum
• Fuchsia in color
• Located on floors 4 5

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Electron Configuration Practice

• Complete the electron configurations for the
  following elements

1s2 2s2 2p6 3s2
1s2 2s2 2p6 3s2 3p6 4s2 3d10 4p6
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• Orbital Diagrams
• Aufbau principle
• -each electron occupies the lowest energy
  orbital
• available.
• Pauli exclusion principle
• -maximum of two electrons may occupy a single
• orbital
• Hunds rule
• -single electrons with the same spin must occupy
  
• equal energy orbital before an
  additional electron
• of an opposite spin can occupy the
  same orbitals.

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Orbital Diagrams

• Mg ___ ___ ___ ___ ___ ___
• 1s 2s 2p
  3s

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Orbital Diagrams
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Noble Gas Notation for Electron Configuration
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Example Bohr Model Sodium (Na)

• Atomic Number
• 11
• Protons
• 11
• Neutrons
• 12
• Electrons
• 11

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Valence Electrons

• Electrons in the atoms outermost orbitals
• Orbitals are associated with the atoms highest
  principal energy level
• These electrons will be the ones involved in
  reactions
• Use the valence electrons to complete the
  electron dot structure.
• Na 1s22s22p63s1
• Sodium has ONE valence electrons

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Group Name Valence e-
1A Alkali 1
2A Alkaline Earth Metals 2
3A Boron Group 3
4A Carbon Group 4
5A Nitrogen Group 5
6A Oxygen Group 6
7A Halogen 7
8A Noble Gases 8
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Electron Dot Structure

• Elements symbol represents the atomic nucleus and
  inner electrons
• Symbol is surrounded by dots representing the
  valence electrons.
• Apply one dot per side and then pair up
• Li O Ne Mg

Na
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