Download Quantum Numbers, Spectra Calculations

Quantum Numbers, Spectra
Calculations
• Objective
– Today I will be able to:
• Illustrate the location of an electron by drawing an orbital diagram
• Identify the location of valance electrons in an atom
• Identify the properties of the 4 types of quantum numbers
• Determine the quantum numbers for various electrons in an atom
• Calculate frequency, wavelength and energy using the appropriate
equations
• Evaluation/ Assessment
– Informal assessment – student responses when reviewing electron
configuration problems, orbital diagrams, valence electrons, quantum
numbers and spectra calculations on practice sheets
– Formal Assessment – collecting and analyzing students responses to
quantum number and spectra calculations on the practice sheets
Lesson Sequence
• Warm – Up
• Evaluate: Students will draw
orbital diagrams on the board
and explain their answers
(informal assessment)
• Explain: Review Valance
Electrons Notes
• Evaluate: Students will share
responses to the worksheet
• Explore: Students will use a
textbook to research the four
types of quantum numbers
• Explain: Quantum Numbers
• Elaborate: Writing quantum
numbers practice
• Evaluate: Review quantum
numbers practice
• Explain: Electromagnetic
spectra calculations
• Elaborate: Electromagnetic
spectra calculations
• Exit Ticket
Warm - Up
• What are valance electrons?
• How do you determine the number of valance
electrons in an atom?
• How many valance electrons are there in the
following elements:
– Mg
–O
– Ge
– Cr
Objective
• Today I will be able to:
– Illustrate the location of an electron by drawing an
orbital diagram
– Identify the location of valance electrons in an
atom
– Identify the properties of the 4 types of quantum
numbers
– Determine the quantum numbers for various
electrons in an atom
– Calculate frequency, wavelength and energy using
the appropriate equations
Homework
• Spectra Calculations
• STEM Fair Data Table and Graphs Due
Monday, November 26
• Electrons Exam
– A – Day – Thursday, November 15
– B – Day – Friday, November 16
Agenda
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Warm – Up
Review Orbital Diagrams
Review Valance Electrons
Quantum Numbers
Spectrum Calculations
Exit Ticket
Review the Electron Configuration
and Orbital Diagram Practice
Worksheet
Valence Electron Notes
Valence Electrons
• Electrons in the outermost energy level
• Determines the number of electrons an
atom gains, loses, or shares
• These are the electrons that are
involved in bonding
Valence Electrons (skip)
• Write the electron configuration for
oxygen
• 1s2 2s2 2p4
• Oxygen has six valence electrons (2s2 and
2p4)
Valence Electrons (skip)
• Write the electron configuration for
potassium
• 1s2 2s2 2p6 3s2 3p6 4s1
• Potassium has 1 valence electron (4s1)
Valence Electrons
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Exceptions are the d and f sublevels! Use
the number of electrons in the last s sublevel
(and the p sublevel, if available)
Write the electron configuration for Bromine
1s2 2s2 2p6 3s2 3p6 4s2 3d10 4p5
Bromine has seven valence electron (4s2 and
4p5)
Foreshadowing: Octet Rule
• Most atoms want 8 electrons in their
outermost level OR full s and/or p
sublevels
• Atoms will form bonds to achieve the
desired amount of electrons
• Atoms are most stable when they have a
full outer shell
Complete Valence Electrons
Worksheet
Review Valence Electrons
Worksheet as a class
Quantum Numbers Activity
Quantum Numbers
• Quantum numbers tell us properties of the atomic
orbitals, and electrons, in an atom.
• Like giving each electron its own addres
• An orbital is a 3-D region of an atom where there is a
high probability of finding electrons
(NOT an actual ring & NOT like the planetary orbitals)
Principal Quantum
Number
Angular Momentum
Quantum Number
Magnetic Quantum
Number
Spin Quantum Number
Textbook
• You will need a textbook to look up information about the
quantum numbers.
Know for each Quantum #
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Definition
Symbol
The allowed values
An example
A visual representation of the quantum number
Review Quantum Numbers as a
Class
Discussion of the 4 types of quantum
numbers and there properties
Quantum Number Review Notes
Quantum Numbers
• Used to describe various properties of
the orbitals
• Each electron is assigned a set of four
quantum numbers which, in order, are n,
l, ml , and ms
• Like giving each electron its own address
Principle quantum number
• Definition: indicates the main energy level
occupied by the electron
• Symbol: n
• Values: (written as integers) 1,2,3,4,5,6,7
Angular Momentum Quantum Numbers
• Definition: indicates the shape of the orbital
• Symbol: l
• Values:
–0=s
–1=p
–2=d
–3=f
• For a specific energy level, the number of
orbital shapes available is equal to n -1
Magnetic Quantum Numbers
• Definition: represents the orientation of an
orbital around the nucleus
• Symbol: ml
• Values: for a p-orbital -1, 0 , 1
Spin Quantum Numbers
• Definition: represents the spin states of
electrons in an orbital
• Symbol: ms
• Values: +1/2, - ½
Can an e- be described by the following set of
quantum numbers?
n=2, l=1, ml= -1
All quantum numbers are allowed values
Can an e- be described by the following set of
quantum numbers?
n=1, l=1, ml= +1
Not possible.
The value of l must be less than the value
of n.
Can an e- be described by the following set of
quantum numbers?
n=7, l=3, ml= +3
All the quantum numbers are allowed
values.
Can an e- be described by the following set of
quantum numbers?
n=3, l=1, ml=-3
Not possible.
The value of ml must be in the range
-l to +l
Replace the ? Mark with an
appropriate quantum number.
n=3, l=1, ml=?
n=4, l=?, ml=-2
n=?, l=3, ml=?
Can an e- be described by the following set of
quantum numbers?
n=2, l=1, ml=-2
n=3, l=2, ml=+2
n=4, l=3, ml=+3
n=5, l=2, ml=+3
Writing Quantum Numbers
• You can identify the quantum numbers for any
electron in an element
• Start by writing out the the electron
configuration and orbital diagram for the
element
• Locate the electron in the orbital diagram that
you are solving the quantum number for
• Determine the 4 quantum numbers
Hydrogen’s electron
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Write electron configuration
Draw orbital diagram
n= 1
l= 0
ml= 0
ms= +1/2
Helium’s second electron
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Write electron configuration
Draw orbital diagram
n= 1
l= 0
ml= 0
ms= -1/2
Lithium’s third electron
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Write electron configuration
Draw orbital diagram
n= 2
l= 0
ml= 0
ms= +1/2
Flourine’s 6th electron
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Write electron configuration
Draw orbital diagram
n= 2
l= 1
ml= 0
ms= +1/2
Review Notes: Spectra
Calculations
Electromagnetic Spectrum
Electromagnetic Spectrum
Electromagnetic Spectrum
• Wavelength (λ - lambda) – distance between
crests in a wave
- Measured in meters or nanometers
• Frequency (v - nu) – number of complete waves
passing a point in a given amount of time
- Measured in Hertz (Hz)
• (λ)(v) = c (velocity of light = 3.0 x 108 m/s)
• Amplitude - distance from wave origin to peak or
crest
Electromagnetic Spectrum
 Visible light has a wavelength of about 10-6 m
 The frequency of visible light is about 3 x 1014 Hz
 The range of visible light is between 200 nm and
900 nm
 Most sunlight available at ground level is between
400 nm and 700 nm, because our atmosphere
strongly absorbs both longer and shorter
wavelengths
- The human eye is most sensitive in this range
Electromagnetic Spectrum
• The light of the sun is called White Light,
and contains all the colors of the visible
spectrum
• Violet (400 nm)  Red (700 nm)
• Objects appear to us to be the color that
is being reflected (chlorophyll)
Max Planck
• Scientists wondered why different ranges of
wavelengths are emitted at different
temperatures
• Ex: A space heater getting warmer
• Max Planck – Energy emitted or absorbed by
an object is restricted to “pieces” of particular
size
- He called these pieces quantum, which
means fixed amounts
Max Planck
• Max Planck (continued)
- E = hυ (equation developed by Einstein)
- h = Planck’s constant
(6.6262 x
10-34 J-s)
- E = energy
- υ = frequency of radiation
• Notice h is very small. Each quantum of energy is
very small
• Used by astronomers to determine the temperatures
of distant planets and stars by measuring the
wavelengths of the EM radiation they emit
Example
• What is the energy associated with a wave that
has a frequency of 4.74 x 1014 Hz?
• E = hυ
• E = (6.6262 x 10-34 J-s) x (4.74 x 1014 Hz)
• E = 3.14 x 10-19 J
Wavelength, Frequency and
Energy Calculations
Complete the worksheet.
Be sure to show all work
Review Energy, Frequency and
Wavelength Calculations
Students will record samples on the
board
Exit Ticket
• What are the quantum numbers for the last
electron in Neon?