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HONORS CHEMISTRY

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Title: Atoms, Isotopes and Ions Author: asu Last modified by: Windows User Created Date: 11/5/2006 9:27:18 PM Document presentation format: On-screen Show (4:3) – PowerPoint PPT presentation

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Title: HONORS CHEMISTRY


1
HONORS CHEMISTRY
  • September 9, 2013

2
Atomic History
  • Democritus
  • Dalton
  • JJ Thomson
  • Rutherford
  • Chadwick
  • Bohr
  • Matter is composed of empty space in which atoms
    move
  • Elements consist of atoms and compounds are
    collection of atoms
  • Plum pudding model Atoms contain negative
    particles called electrons
  • Alpha particles, positive charge with a mass
    7500x of electron. Proved the plum pudding model
    was wrong. Nucleus center ( ) and tiny electrons
    moved in space around it.
  • Discovered neutrons (slightly more massive than a
    proton).
  • Electrons are in circular paths depending on
    their energy levels

3
Atomic History
  • De Broglie
  • Schrodinger
  • Millikan
  • Moseley
  • electrons move in waves rather than straight
    circular paths
  • Wave Mechanical Model or Quantum Mechanical
    Model. Furthered De Broglies idea of waves by
    stating that electrons are in clouds but in
    certain energy region
  • Oil drop experiment discovered that atoms had
    positive and negative charges and that they equal
    each other
  • Helped to arrange atoms in the periodic table.
    Atoms were arranged in increasing atomic number
    using wavelengths and
  • x-rays

4
Atoms, Isotopes and Ions
  • How do atoms of different elements differ?

5
The Modern View of Atomic Structure
  • What are the particles that make up an atom and
    how do they differ from one another?
  • proton mass 1 amu charge 1
  • neutron mass 1 amu charge 0
  • electron mass 0 amu charge -1
  • 1 amu 1.6726 x 10-27 kg

02m14an1
1/1840
  • atoms have equal numbers of protons and electrons
    so they are electrically neutral

6
Atomic Number
  • Atomic number
  • Number of protons in an atom
  • Identifies the element

12.01115
7
Atomic Number
  • Use the Periodic Table to complete the following.
  • 1. What element has the atomic number 18?
  • 2. What element has 35 protons?

8
How are atoms of one element different from those
of another element?
  • They have different numbers of these subatomic
    particles.

Atomic Number
Chemical Symbol
Element Name
1.00797
Average Atomic Mass
9
Isotopes
  • How do we distinguish between atoms?
  • Do all atoms of an element have the same
    composition?
  • Heavy Water and Water Ice Cube in water

10
Isotopes
  • What implication does this have for the masses of
    atoms?
  • Average atomic mass
  • Isotopes differ only in the number of Neutrons
  • Difference is shown by their mass numbers
  • Notation superscript for mass number, which is
    the sum of the number of protons and neutrons
  • Notation subscript for atomic number, which is
    the number of protons (or electrons)
  • 73Li 94Be 115B

11
Nuclear Particles
  • How many of each particle (protons, neutrons and
    electrons) are in these atoms?
  • 7635 Br 7835Br
    8035Br
  • 147N 157N
  • 188O 178O 168O 158O

12
Ions
  • When an atom loses or gains electrons and
    acquires a net electrical charge.
  • Gain electrons negative ion - anion
  • Lose electrons positive ion - cation

Mg2
Mg
13
Ions
  • Charge of ion of protons - of electrons
  • How many protons, neutrons and electrons does
    4120Ca2 have?
  • How many protons, neutrons and electrons does
    7835Br - have?

14
Think-Pair-Share
  • Atomic Structure Worksheet

15
Closure
  • 1. How many protons, neutron and electrons does
    Mg have?
  • 2. How many protons, neutron and electrons
  • does 74Be -2 have?

16
HONORS CHEMISTRY
  • September 10, 2013

17
Brain Teaser
  • Place homework on your desk
  • How many protons, neutrons and electrons does
    3211Na 1 have?
  • Who developed the planetary model of the atom
    based on quantum energy levels
  • Who discovered that most of the atoms mass is
    located in the nucleus of an atom and the atom is
    mostly empty space
  • Who discovered the electrons and developed the
    plum pudding model of the atom

18
Agenda
  • Brain Teaser
  • Grade Homework Atomic Structure Worksheet
  • Notes
  • Wave and Particle Nature of Light
  • Line Spectra
  • Quantum Theory
  • Bohr Models
  • Homework
  • Bohrs Model Worksheet/Isotope Worksheet

19
Review (Insert)
  • Mass of Proton 1.67 x 10-24 grams 1 amu
  • Mass of Neutron 1.67 x 10-24 grams 1 amu
  • Mass of Electron 9.1 x 10-28 grams (essentially
    zero)

20
Unit 3 Light and Quantized Energy Electron
Configuration
  • Objective
  • Learn how electrons are arranged in an atom and
    how that arrangement plays a role in their
    chemical behavior

21
How do we know what makes up an atom?
22
The Atom is a Scientific Model
  • With the scanning tunneling microscope we can see
    atoms, but we still cannot see their internal
    structure.
  • Scientific models are created by experiments, but
    are often modified.
  • There may be flaws in the current model.

23
What do atoms look like?
  • See the electron microscope image of the
    molecular art drawn with gold (Au) atoms.
  • See the image of graphite. Are these images
    proof of atoms? How do we see atoms?

nickel
benzene
graphite
24
How do we know what makes up atoms?
25
Cathode Ray Tubes
  • Why does the beam bend?

26
Gold Foil Experiment
  • Examine the diagram of Rutherfords alpha ray
    experiment. What is the implication of this
    experiment?

27
Line Spectra
  • Bright Line Spectra
  • Lines of color produced by light emitted from
    heating substances and passing them through a
    prism
  • Fingerprints of elements
  • Researchers can determine values of energy levels
    in atoms
  • Used to identify different elements

28
Observation of unique line spectra led to Quantum
Theory
Eh?
Fourth
Third
Second
First
Nucleus
29
  • Demo
  • Point Spectroscope towards the fluorescent light
    bulb
  • Observe the bright line spectrum of mercury and
    phosphorous

30
Where all of this has led to
  • Bohr Model did some good things but it is not
    the whole truth.

31
Some Questions
  • Color arises from electrons shifting from one
    orbital to another of different energy
  • Ground state and excited state
  • What shift would give rise to emission of light?
    to absorption of light?

32
Where all of this has lead to
  • Quantum Model

33
What is the Quantum Mechanical Model?
  • It predicts quantized energy levels for
    electrons, like the Bohr model.

34
What is Quantum Theory?
  • It does not describe the exact path that
    electrons take around the nucleus of an atom, but
    is concerned with the probability of an electron
    being in a certain place.

35
Nucleus
36
Orbitals
  • Areas where an electron can be found
  • Can have up to two electrons
  • Fuzzy boundaries ? Electron Cloud

37
The Closed Sphere Model
  • For convenience
  • Shows where the electron is 90 of the time

38
The Heisenberg Uncertainty Principle
  • You can never know exactly where an electron is
    if you know exactly how fast it is moving.
  • You can never know exactly how fast an electron
    is moving if you know exactly where it is.

39
Bohr Diagram Practice Worksheet
40
THE END
41
HONORS CHEMISTRY
  • September 12, 2012

42
Brain Teaser
  • Place Homework on your desk
  • Write the complete symbol from the given
    information below
  • 20 protons, 22 neutrons, 18 electrons
  • 15 protons, 17 neutrons, 18 electrons
  • 17 protons, 18 neutrons, 17 electrons
  • How many protons, neutrons, and electrons are
    there for each of the following atoms or ions?
  • 12 B3
  • 80 35 Br

43
Agenda
  • Brain Teaser
  • Grade Homework
  • Bright Line-Emission Spectra
  • Practice Quiz
  • Homework
  • Study for Quiz (Friday)

44
Grade Homework
  • Bohr Diagram Worksheet
  • Look for patterns
  • Period
  • Group
  • Label Periodic Table
  • Isotopes Worksheet

45
Bright Line Emission Spectra Lab Activity
  • Objective
  • Identify different metals through flame tests and
    using bright line emission spectra

46
Background
  • Light Electromagnetic radiation
  • Frequency of light relates to energy (Diagram)
  • Higher Frequency Higher Energy
  • Frequency and Color are related
  • (Low)Radio, M, IR, Visible, UV, X-Ray, Gamma
    Ray(High)
  • Visible Light (Lower) R O Y G B I V (Higher)
  • White light has all the colors
  • Prism/Diffraction Gratin ? Breaks up colors
  • Gaseous element contained in a tube ? energize it
    with electricity ? glow/gives off visible light

47
Background
  • Electrons absorbing energy excited
  • Electrons giving off energy ? Gives off light
  • All atoms have all energy levels but they may
    not have e- on them. (Diagram)
  • e- jumps to a higher energy level excited state
  • e- will give off energy/falls back down ? give
    off visible light (lowest possible energy level
    ground state)
  • Energy of photon is proportional to the color
  • Some energy are given off as invisible spectrum
    like IR or UV
  • Red photon is lower in energy compared to blue
    photon

48
Background
  • Tube filled with Ne, H, or He (discrete lines) ?
    Atomic Emission Spectra
  • e- cannot have any amount of energy but only
    certain amount of energy (no in b/w color)
  • Evidence only certain colors are given off.
    e- exist only at certain distances from
    the nucleus
  • Every element has a unique emission spectrum
    because it has different electron configuration
  • Emission Spectra as a fingerprint of elements
  • Applications Astrophysics or Forensics

49
Background
  • Electrons are only allowed in certain energy
    levels, only have a certain amount of energy, can
    only give off a certain amount of energy
    (quantized energy)
  • Different elements have different frequencies and
    they give off a different set of colors

50
Line Spectra
51
Observation of unique line spectra led to Quantum
Theory
Eh?
Fourth
Third
Second
First
Nucleus
52
Element Finger Print
07m07an1
53
Spectroscopes
  • Practice using the Spectroscopes
  • What do you see?
  • Where is it coming from?

54
Lab Line Spectrum Station Rotation
At each Station
  • Spectra
  • Observe through spectroscope
  • Record measurements and notes
  • Switch roles to judge precision of observation
  • Data Analysis
  • Compare spectra to various reference sources
  • Identify substance
  • Work on study questions

55
Lab Rotation
  • Identify the emission spectra for 5 gas tubes and
    4 stations for Flame tests
  • Flame test Dip the sticks in water and WEAR
    GOGGLES!
  • Use colored pencils to mark the reference for
    each station (Gas Tubes)
  • Use colored pencils to mark the reference for
    Flame Tests
  • Write a qualitative analysis on each emission
    spectrum

56
Questions?
57
Color Coding the Periodic Table Activity
  • Read handout
  • Fill out Family Ties (Student Worksheet)
  • Homework
  • Study for Quiz (Friday)

58
Start
59
Lab Line Spectrum Station Rotation
At each Station
  • Pair A
  • Spectra
  • Observe through spectroscope
  • Record measurements and notes
  • Switch roles to judge precision of observation
  • Pair B
  • Data Analysis
  • Compare spectra to various reference sources
  • Identify substance
  • Work on study questions

60
Spectroscopes
  • What do you see?
  • Where is it coming from?

61
Line Spectra
62
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63
HONORS CHEMISTRY
  • September 17, 2012

64
Brain Teaser
  • Explain why each element can produce its own
    bright line spectrum

65
Agenda
  • Brain Teaser
  • Pre-Test Periodic Trends
  • Notes
  • Bohrs Model
  • Orbital Diagrams and Electron Configuration
  • Practice Writing electron configuration
  • Homework
  • Electron configuration worksheet

66
Bohr's Model
  • Model of electrons in fixed orbits to explain
    quantization Figure 6.14
  • Transitions between orbits emits or absorbs light

07m07an1
67
Observation of unique line spectra led to Quantum
Theory
Eh?
Fourth
Third
Second
First
Nucleus
68
Orbital Diagrams and Electron Configurations
  • n Principle quantum number
  • Describes the energy level the electron occupies

n 4
n 3
n 2
n 1
69
Orbital Energy Levels
  • Shape of orbital
  • designated by the
  • letters
  • s, p, d, f, g

Excited states
Ground state
70
Shapes of Orbitals
  • Shape of orbital designated by the letters
  • s, p, d, f, g
  • Orbitals have different shapes

71
s Orbital shape
The s orbital has a spherical shape centered
around the origin of the three axes in space.
72
p orbital shape
There are three dumbbell-shaped p orbitals in
each energy level above n 1, each assigned to
its own axis (x, y and z) in space.
73
d orbital shapes
Things get a bit more complicated with the five d
orbitals that are found in the d sublevels
beginning with n 3. To remember the shapes,
think of double dumbells
and a dumbell with a donut!
74
Shape of f orbitals
75
Combination of electron microscopy and
x-ray diffraction produced image of orbitals
76
Sets of Orbitals (Subshells)
  • Depending on the type of orbital, we find that
    they occur in sets differing in their orientation
    in space
  • s - set of 1
  • p - set of 3
  • d - set of 5
  • f - set of 7

77
Sizes of orbitals
  • Size depends on the value of n
  • Orbitals with the same n are about the same size

78
Check for understanding
  • What is the principal quantum number for Ar?
  • What are the subshells?
  • How many sets of electrons are found in each
    subshell?

79
Electron Configurations of Some Atoms
  • The first ten elements
  • 1s1
  • 1s2
  • 1s2 2s1
  • 1s2 2s2
  • 1s2 2s2 2p1
  • 1s2 2s2 2p2
  • 1s2 2s2 2p3
  • 1s2 2s2 2p4
  • 1s2 2s2 2p5
  • 1s2 2s2 2p6

80
Shorthand Notation for Orbitals
  • Combinations of first two quantum numbers number
    of orbital types equals the shell number (n).
  • 1s
  • 2s, 2p
  • 3s, 3p, 3d
  • 4s, 4p, 4d, 4f
  • 5s, 5p, 5d, 5f, (5g)
  • 6s, 6p, 6d, 6f, (6g, 6h)
  • (Stop Period 5)

81
HONORS CHEMISTRY
  • September 18, 2012

82
Brain Teaser
  • Place Homework on your desk
  • Write the Electron Configuration for the
    following elements
  • Si
  • Co
  • Se

83
Agenda
  • Brain Teaser
  • Grade Worksheet
  • Review
  • Writing Electron Configuration
  • Notes Orbital Diagram
  • Homework
  • Short Hand Electron Configuration
  • Orbital Diagram

84
Grade Homework
  • Refer to Worksheet (Arrangement of Electrons I)

85
Check for understanding (P6)
  • What is the principal quantum number for Ar?
  • What are the subshells?
  • How many sets of electrons are found in each
    subshell?

86
Aufbau Principle
  • Aufbau Principle start with the nucleus and
    empty orbitals, then build up the electron
    configuration using orbitals of increasing energy

87
Electron Configurations
  • Electron Spin and Pauli Exclusion Principle
  • Only two electrons can occupy a single orbital
    and they must have opposite spins

88
Electron Configurations
  • Hund's Rule
  • When filling a subshell, such as the set of 3 p
    orbitals, place 1 electron in each before pairing
    up electrons in a single orbital

89
Electron Configurations
  • Arrangement of electrons in the orbitals is
    called the electron configuration of the atom
  • The ground state configuration can be predicted,
    using the Aufbau Principle, the Pauli Exclusion
    Principle, and Hunds Rule.

Electron configurations
Filling _ rules.exe
90
How do we know what the filling order is?
  • What chemistry tool might we rely on?

91
Electron Configurations and the Periodic Table
  • Valence electron configurations repeat down a
    group

92
Ground state electron configurations
  • Example Li
  • atomic number 3
  • nucleus has 3 protons
  • neutral atom has 3 electrons
  • 2 electrons in 1s orbital, 1 electron in 2s
    orbital

2s
1s
93
Different ways to show electron configuration
Box notation
Energy level diagram
?
??
2s
2s
1s
1s
Spectroscopic notation
Li 1s2 2s1
Read this one s two not one s squared
Write the superscript 1. Dont leave it blank
94
Practice
  • Review (on separate sheet of paper)
  • Electron Configuration
  • Orbital Diagram
  • Electron configuration worksheet

95
Using the Periodic Table
  • The last subshell in the electron configuration
    is one of these
  • (row ) s (row 1) d
  • (row ) p (row 2) f

96
The f-block is inserted into to the d-block
97
Electron configuration of O
  • Atomic number of O 8 so neutral atom has 8 e

98
Electron configuration of Co
  • Atomic number of Co 27 so neutral atom has 27
    e

99
Simplifying electron configurations
  • Build on the atoms noble gas core
  • He 1s2
  • O 1s22s22p4
  • O He2s22p4
  • Ar 1s22s22p63s23p6
  • Co 1s22s22p63s23p64s23d7
  • Co Ar4s23d7

??
?
?
??
??
1s
2s
2p
??
??
??
??
??
??
??
??
??
??
??
?
??
?
?
1s
2s
2p
3s
3p
4s
3d
100
Noble Gases
  • Far right of the periodic table
  • These elements are extremely unreactive or inert
  • They rarely form compounds with other elements

101
Noble Gas electron configurations
  • What is the electron configurations for Neon
  • Abbreviated way to write configurations
  • Start with full outer shell then add on
  • Br
  • Ba

102
Noble Gases
  • Neon- emits brilliant light when stimulated by
    electricity neon signs- 4th most abundant
    element in the universe.
  • Helium- light non reactive gas- used balloons-
    inexpensive, plentiful and harmless
  • Radon- radioactive gas- can cause cancer-
    colorless, odorless emitted from for certain
    rocks underground

103
(No Transcript)
104
Why are we doing all of this?
  • Properties of atoms correlate with the number and
    energy of electrons
  • Electron configurations are used to summarize the
    distribution of electrons among the various
    orbitals

105
Practice
  • 3-3 Practice
  • Write the complete electron configurations and
    noble gas shorthand 1-4

106
Practice
  • Refer to a periodic table and write the electron
    configurations of these atoms.
  • Write the configurations using shorthand
    notation.
  • Zn
  • I
  • Cs

107
The f-block is inserted into to the d-block
108
Find the electron configuration of Au
  • Locate Au on the periodic table

109
Find the electron configuration of Au
  • Au Xe
  • The noble gas core is Xe

110
Find the electron configuration of Au
  • Au Xe6s2
  • The noble gas core is Xe
  • From Xe, go 2 spaces across the s-block in the
    6th row ? 6s2

111
Find the electron configuration of Au
  • Au Xe6s24f14
  • The noble gas core is Xe
  • From Xe, go 2 spaces across the s-block in the
    6th row ? 6s2
  • Then detour to go 14 spaces across the f-block ?
    4f14
  • note for the f-block, n row 2 6 2 4

112
Find the electron configuration of Au
  • Au Xe6s24f145d9
  • The noble gas core is Xe
  • From Xe, go 2 spaces across the s-block in the
    6th row ? 6s2
  • Then detour to go 14 spaces across the f-block ?
    4f14
  • note for the f-block, n row 2 6 2 4
  • Finally go 9 spaces into the d-block on the 6th
    row ? 5d9
  • note for the d-block, n row 1 6 1 5

113
Electron configuration of ions
  • What is an ion?
  • How many electrons does Cl1- have?
  • What is the electron configuration for the
    chloride ion?
  • How many electrons does Ca2 have?
  • What is the electron configuration for the
    calcium ion?
  • What do you notice?

114
Practice
  • Draw the orbital diagram for sulfur.
  • What ion does sulfur want to form and why?
  • Draw the orbital diagram for Potassium.
  • What ion does sulfur want to form and why?

115
What does this mean
  • Properties of atoms correlate with the number and
    energy of electrons
  • Atoms like to have full outer shells.

116
Why is this important
  • Valence electrons
  • Electrons in the outermost energy level
  • Where all the action occurs

117
Practice
  • Whiteboard - Atomic Structure (continued)

118
Team
  • Write the electron configuration for silver.
  • Write the noble gas configuration for silver.
  • What element has the following electron
    configuration?
  • 1s22s22p6 3s23p64s23d4

119
Today we use aspects of line spectrum to identify
elements, compounds and mixtures?
  • UV-Vis Spectrometer
  • Distances and types of stars
  • Blood test- carbon monoxide poisoning
  • Mobile weapons detectors
  • Chlorophyll

120
How we determine these energy levels?
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