Chapters 4 and 5

1
Electrons in Atomsand The Periodic Table

• Chapters 4 and 5

2
Unanswered Questions

• Where are the electrons placed around the
  nucleus?
• Why are the electrons NOT pulled into the
  nucleus?
• Opposites attract
• Answers came from a new understanding of LIGHT.

end
3
Properties of Light- Wave

• Visible light is a part of the Electromagnetic
  (EM) Spectrum
• Energy moving like a wave
• Last page of Reference Tables
• Wavelength (?)
• Distance between 2 identical points
• Meters
• Frequency (?)
• Number of waves in 1 second
• Hertz (Hz) or 1/s

end
4
Properties of Light- Wave

• All EM waves travel at the Speed of Light (c)
• c 3.0 x 108 m/s

• As Wavelength goes up
• Frequency goes down
• Energy goes down

end
5
Properties of Light- Wave

• A gamma ray has a wavelength of 7 x 10-13 m.
  What is the frequency of this ray?
• A satellite transmits on the EM Spectrum at a
  frequency of 9.4 x 109 Hz. What is the signals
  wavelength?
• What type of wave is being transmitted?
• A beam of visible light has a frequency of
  4.5x1014 Hz.
• What is the wavelength of this light?
• What color is this light?

end
6
Properties of Light- Particle

• Light does not always act like a wave
• The Photoelectric Effect
• Metal gives off electrons when light shines on it
• Depends on the frequency
• Not the amount
• Max Planck
• Energy is gained/lost energy in specific amounts
  known as Quanta

Frequency
Energy
Plancks Constant (6.626 x 10-34 Js)
end
7
Properties of Light- Particle

• What is the energy of an EM wave with a frequency
  of 6.32 x 1026 Hz?
• What energy would a beam of microwaves have if
  their wavelength is 5.6 x 10-2 m?
• A beam of visible light has a wavelength of 5.8 x
  10-7 m. What is its energy and what color is it?

end
8
Properties of Light- Both???

• Albert Einstein
• Wave-Particle Duality
• EM waves can act as both a wave and a particle
• Photon
• A particle of light

end
9
Emission Spectrum

• Atomic Emission Spectrum
• Every element gives off specific frequencies of
  light

end
10
Emission Spectrum
O2
end
11
Properties of Light
Wavelength (meters)
3.0 x 108 m/s
Frequency (Hertz- Hz)

• A gamma ray has a wavelength of 7 x 10-13 m.
  What is the frequency of this ray?
• A satellite transmits on the EM Spectrum at a
  frequency of 9.4 x 109 Hz. What is the signals
  wavelength?
• What type of wave is being transmitted?
• A beam of visible light has a frequency of
  4.5x1014 Hz.
• What is the wavelength of this light?
• What color is this light?

end
12
Properties of Light
Energy (Joules- J)
Frequency
Plancks Constant (6.626 x 10-34 Js)

• What is the energy of an EM wave with a frequency
  of 6.32 x 1026 Hz?
• What energy would a beam of microwaves have if
  their wavelength is 5.6 x 10-2 m?
• A beam of visible light has a wavelength of 5.8 x
  10-7 m. What is its energy and what color is it?

13
Bell Ringer

• Light can be a particle and wave energy.
  True/False
• The Frequency of a Light is 7.5 x 1014 Hz. What
  is its wavelength?
• What type of light is it?
• What is light as a particle called?
• Compare Frequency, Energy, and Wavelength of a
  Gamma Ray, and a Microwave.
• You need your ipad, reference table out today!

14

• _________ P
• B
• ______________ N
• _______ E

15
Atomic Theories- Bohr

• Niels Bohr
• e- placed into Energy Levels (n)
• Rings around the nucleus
• of electrons in each orbit 2n2
• Cannot be between energy Levels
• Gain Energy e- move up levels
• To an Excited State
• Release Energy e- move down levels
• To the Ground State
• Bigger Move More Energy

end
16
BOHR MODEL PRACTICE
17
Atomic Theories- Bohr

• If an electron drops from n3 to n2 what would
  be the approximate wavelength of the light
  emitted?
• If an electron drops from n4 to n1 what type of
  EM radiation would be produced? What is its
  wavelength?

end
18
Atomic Theories- Bohr

• Determine the wavelength, frequency, and type of
  EM wave for each of the following transitions.
• n 4 ? n 1
• n 5 ? n 2
• n 6 ? n 3

end
19
(No Transcript)
20
(No Transcript)
21
Atomic Orbitals Quantum Numbers

• Electron Cloud Model
• e- orbit nucleus in Atomic Orbitals
• Area with 95 chance of finding an e-
• Each orbital holds 2 e-
• e-s position (address) given with 4 Quantum
  Numbers
• The Principal Quantum Number (n)
• Indicates the Energy Level
• 1, 2, 3, 7
• Bigger Numbers Higher Energy
• Each level has sublevels

end
22
Atomic Orbitals Quantum Numbers

• Angular Momentum Quantum Number (l)
• Shape of the sublevel
• Labeled s, p, d, f,

• p
• Dumbell (Peanut)
• 3 orbitals in each Energy Level
• Total e- 6

• s
• Sphere
• 1 orbital in each Energy Level
• Total e- 2

end
23
Atomic Orbitals Quantum Numbers

• d
• 5 orbitals in each Energy Level
• Total e- 10

4 Daisy
1 Peanut in a Doughnut

• f
• 7 orbitals in each Energy Level
• Total e- 14

end
24
(No Transcript)
25
(No Transcript)
26
(No Transcript)
27
(No Transcript)
28
(No Transcript)
29
Electron Configuration

• e- are arranged according to 3 rules
• Aufbau Principle
• e- will occupy the LOWEST energy level
• n 1 is the lowest
• Sublevels s lt p lt d lt f
• d and f overlap with the next Energy Level

end
30
Electron Configuration

• Pauli Exclusion Principle
• ONLY 2 e- in each ORBITAL
• e- MUST have opposite Spins

end
31
Electron Configuration

• Hunds Rule
• 1 e- in each orbital of a sublevel before you can
  double up

Unpaired Electrons
Paired Electrons
end
32
Electron Configuration

• Orbital Notation
• Draw line and label each Energy Level and
  Sublevel
• Add arrows to represent electrons
• Li
• O
• Cl
• Ne
• Ca
• V

end
33
Electron Configuration

• Electron Configuration Notation
• Instead of drawing all of the lines, use
  superscripts
• Be
• F
• Mg
• He
• Ar
• B

end
34
The Periodic Table

• By 1860 scientists had discovered 63 elements
• They were organized by Mendeleev
• Mendeleevs Periodic Table
• Similar Properties Same Column
• Mass increased along each row

end
35
The Periodic Table

• Blank spaces for undiscovered elements
• Correctly predicted their properties

end
36
The Periodic Table

• The Modern Periodic Table
• Based on Mendeleevs table
• Similar Properties Same Column (Group)
• Atomic Numbers increase along each Row (Period)

end
37
(No Transcript)
38
(No Transcript)
39
The Periodic Table

• To make everything fit on 1 page, the Lanthanides
  and Actinides are moved to the bottom

end
40
Electron Configuration and the P.T.
Energy Levels (n)
1
2
3
4
3
4
5
5
6
7
6
4
5
end
41
Electron Configuration and the P.T.
Sublevels (l)
p
s
d
f
end
42
Electron Configuration and the P.T.

• Instead of the Aufbau diagram, read the Periodic
  Table
• Add 1 electron for each element you pass
• N
• Si
• Ti
• Mg
• Mo
• I

end
43
Electron Configuration

• Noble-Gas Notation
• Find the Noble Gas before the element
• Write Symbol, then continue with the electron
  configuration
• Follow the Periodic Table
• Na
• Al
• K
• S As Sn

end
44
Chapter 5 Periodic Table Trends
45
Bell Ringer

• Draw a Bohr Model for the following elements
• Phosporous
• Write the electron configuration
• Write the orbital configuration
• How many electrons are in the highest energy
  level for this elements?

46
The Periodic Table

• Valence Electrons
• Electrons in the highest energy level
• Give Elements their Chemical Properties
• Atoms want 8 Valence Electrons (an Octet)
• Filled s and p orbitals
• Find valence electrons for
• N
• Mg
• As
• Ar K Y

end
47
The Periodic Table

• The number of valence electrons can be read off
  of the P.T.
• Group 1 2 13 14 15 16 17 18
• of 1 2 3 4 5 6 7 8
• Valence

end
48
The Periodic Table

• Metals
• Closer to Francium (Fr) More Reactive
• Conductors
• Mostly solids
• High melting/boiling points
• Malleable
• Nonmetals
• Closer to Fluorine (F) More Reactive
• Poor conductors
• Mostly gases
• Low melting/boiling points
• Brittle

end
49
The Periodic Table

• Metalloids
• Touching the stair-step line
• Properties depends on temperature

end
50
The Periodic Table

• Alkali Metals
• EXTREMELY REACTIVE!
• Transition Metals
• Wide Range of Properties
• Lanthanide and Actinide Series
• All are radioactive

end
51
The Periodic Table

• Halogens
• Highly Reactive
• Noble Gases
• Extremely Unreactive
• THEY DO NOTHING!

end
52
Periodic Trends
Increasing

• Atomic Radius
• Closer to Fr Larger Atom
• Ionic Radius
• Metals Lose Valence Electrons
• Positive Charge (Cation)
• Get Smaller
• Nonmetals Gain Valence Electrons
• Negative Charge (Anion)
• Get Larger

end
53
Periodic Trends

• Ionization Energy (IE)
• Energy needed to remove 1 electron
• Metals give up e-
• Nonmetals must be forced

Increasing
end
54
Periodic Trends

• Electronegativity (EN)
• How much at atom attracts an electron
• Metals do NOT attract electrons
• Low electronegativities
• Nonmetals LOVE electrons
• F has the highest NOT He

Increasing
end
55
(No Transcript)