Electron Properties and Arrangement
Chapter 5
Objectives:
• Identify properties of electrons.
•
Understand how electrons move in atoms.
•
Distinguish between atoms based on their different
electron arrangements. .
Electrons in Atoms
1. Using Bohr’s model illustrate and label the
subatomic particles in the following neutral
atoms:
a. Li-4
b. C-14
c. Na-24
2. What do you know about electrons in atoms?
Bohr’s Model of the Atom
•Electrons travel in fixed, circular paths
around the nucleus.
•Each path has a specific energy requirement.
•These circular paths are called energy
levels.
•Limited number of electrons on each
energy level. (2n2 Rule)
http://micro.magnet.fsu.edu/
Electron Properties and Arrangement
Chapter 5
Due:
• Bohr’s Atomic Model Worksheet
Objectives:
• Identify the properties of electrons.
• Understand how electrons are arranged in atoms.
• Understand how electrons move in atoms.
.
Bohr’s Atomic Model Worksheet
Check For:
• All atoms are neutral atoms.
• Remember electrons should be placed on energy
levels (rings) around the nucleus.
• Limited number of electrons on each energy
level, 2n2 Rule
Ex. nitrogen atom
Electrons and Light Particles
Electron Properties:
• Very tiny particles
• Extremely small masses
• Move at very high speeds (3.0x108 m/s)
• Electron movement is identified by the
absorption and emission of light particles by
electrons.
Current Atomic Model
Electrons do not travel in fixed paths around
the nucleus
*Electrons constantly move to different
energy levels in the electron cloud.
*Direction of e- movement is
dependent upon energy absorbed or
released.
*Electrons move around the nucleus in
different shaped paths.
Erwin Schrodinger
Electron Movement
•Ground state: lowest energy level for
an electron
•Photon: light particle that contains energy
Excited state: movement of electron to
higher energy level
Electromagnetic Radiation Spectrum
•Electromagnetic Spectrum : Divides light particles into
regions based on their wave-like properties.
a. Relationship b/w wavelength and frequency?
b. Relationship b/w wavelength and energy emission?
c. Relationship b/w frequency and energy emission?
ICP :Electron Properties 11.13
Infinite Campus Update:
• Electromagnetic Spectrum Analysis Questions
Objectives:
• Identify properties of electrons.
• Understand how electrons move in atoms.
• Distinguish between atoms based on their electron
arrangement.
Homework:
• Read thru lab and complete pre-lab questions.
• Electron Arrangement Worksheet
ICP:Bell Ringer
.1.
What is the maximum number of electrons on the 5th
energy level?
2. Illustrate how an electron can move up and down energy
levels within an atom.
3. a. What is electromagnetic radiation?
b. What are the three wave-like properties scientist use to
distinguish between classes of electromagnetic radiation?
Electron Movement
•Ground state: lowest energy level for
an electron
•Photon: light particle that contains energy
Excited state: movement of electron to
higher energy level
Electromagnetic Radiation Spectrum
•Electromagnetic Spectrum : Divides light particles into
regions based on their wave-like properties.
a. Relationship b/w wavelength and frequency?
b. Relationship b/w wavelength and energy emission?
c. Relationship b/w frequency and energy emission?
Wave-Like Properties: Wavelength
• Wavelength: length of wave from two neighboring crest.
• Amplitude: height of wave from origin to crest.
Wave-Like Properties: Frequency
Frequency (Hz) : how many waves pass a certain point per
second. Hz. =Hertz = (waves/second)
Wave-Like Properties: Energy
• Temperature : Represents amount of energy emitted from
light particles.
• Photons: Light particles classified by energy emitted.
*Electron movement dependent upon type of photons
absorbed or released.
Electromagnetic Spectrum Analysis
• 1
Electromagentic Spectrum Analysis: Check-Up
1. What light particle region emits the least amount
of energy?
2. As wavelength increases for a wave, what
happens to amount of energy emitted?
3. Sketch a line graph illustrating the relationship
(direct or inverse) between wavelength and
energy?
4. Does a yellow light particle or a blue light
particle have a smaller wavelength. Explain your
answer.
Electromagnetic Spectrum Analysis
• Direct Relationship: Move in the same direction.
• Inverse Relationship: Move in different directions.
Which graph represents direct and which represents inverse?
www.shelovesmath.com
Visible Region of EM Spectrum
loke.as.arizona.edu
ICP : Electron Properties 11.13
Infinite Campus Update:
• Wave-Like properties Analysis Qts. (8pts.)
Objectives:
• Identify properties of electrons.
• Understand how electrons move in atoms.
• Distinguish between atoms based on their electron
arrangement.
Homework:
• Complete data and conclusion questions.
Flame Test Lab
Purpose:
• Observe evidence of electron movement when
chemicals are added to a flame.
Procedures:
• Goggles must be worn at all time.
• Do not dip wooden sticks in different solutions.
Data Modifications:
• Include Sr2+ solution and Sn2+ solution
• Mark out following columns:frequency and energy
Flame Test Lab
Post-Lab Questions:
1. What direction is the electron moving
when the flame turns color? Explain.
2. Was the flame test a helpful method in
identifying the unknown solutions?
Explain your answer.
3. Identify which element yielded the coolest
color.
4. What is another example you have
observed of chemicals producing beautiful
colors when they are burned?
Flame Test Lab
Post-Lab Questions:
1. What direction is the electron moving
when the flame turns color? Explain.
2. Was the flame test a helpful method in
identifying the unknown solutions?
Explain your answer.
3. Identify which element yielded the coolest
color.
4. What is another example you have
observed of chemicals producing beautiful
colors when they are burned?
ICP: Electron Properties 11.14
Due:
• Flame Test Lab data and conclusion section.
• Electron Arrangement Practice Sheet (optional)
Objectives:
• Understand how electrons move in atoms.
• Distinguish between atoms based on their electron
arrangement.
Homework:
• Electron Arrangement and Movement Wksht.
Color’s Wavelength
•Each color has its own unique wavelength.
Minerals Colors
• Example of elements that can give minerals their
unique colors.
barium= pale green
strontium = red
copper = blue-green
sodium= yellow
• These are common metals used in fireworks.
Visible Region of EM Spectrum
loke.as.arizona.edu
Doppler Effect
Doppler Effect
• Provides evidence of galaxy movement, Edwin
Hubble.
• Our universe is expanding and at an increasing rate.
• Validates the Big Bang Theory-how our universe
was created.
Chem ICP: Electron Properties 11.15
Objectives:
• Identify properties of electrons.
• Understand how electrons move in atoms.
• Distinguish between atoms based on their electron
arrangement.
• Quiz over electron properties and arrangement
Homework:
• Read and assess article, “Where do Chemical
Elements Come From?”
ICP: Electron Properties 11.18
Infinite Campus Update:
• Midterm grades posted tonight.
• Flame Test Lab (13pts.)
• Electromagnetic Spectrum Analysis qts. (8pts.)
• Electron Properties and Wave Properties Quiz (10pts.)
Due:
• “Where do Chemical Elements Come From?”
Objective
• Identify where color comes from in our natural world.
• Distinguish between atoms based on their electron
arrangement.
“Where do chemical elements come from?”
1. Where do elements come from?
2. How are elements made?
3. What helps astronomers determine the composition
of stars?
4. Briefly summarize a section from this article that
you found most interesting. Explain why.
Emission Spectrum
Emission Spectrum =Reveals what photons are
emitted during electron movement.
Ex. Hydrogen Light
chemed.chem.purdue.edu
Electron Movement
•Ground state: lowest energy level for
an electron
•Photon: light particle that contains energy
Excited state: movement of electron to
higher energy level
Fireworks: Emission of Light
• Example of elements that can give minerals their
unique colors.
barium= pale green
strontium = red
copper = blue-green
sodium= yellow
• These are common metals used in fireworks.
Emission Spectrums
•Emission spectrum for each element is unique.
•Scientist can calculate the energy value of each
emission band.
Elements in Stars
• A star is a sphere of super hot gases—mostly hydrogen
and helium. How do we know this?
Carbon, Oxygen,
Heavier elements 2 %
Nitrogen, & Calcium
Helium
29%
Hydrogen
69%
• Every chemical element has a unique emission spectrum.
• Emission spectrums help astronomers identify the
composition of stars.