Electron Properties and ArrangementChapter 5

Objectives:

• Identify properties of electrons.

• Understand how electrons move in atoms.

• Distinguish between atoms based on their different electron arrangements. .

Electrons in AtomsElectrons 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 AtomBohr’s Model of the Atom

http://micro.magnet.fsu.edu/

•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)

Electron Properties and ArrangementChapter 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 ParticlesElectrons 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 ModelCurrent Atomic ModelElectrons 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 MovementElectron 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 SpectrumElectromagnetic 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 11.13Infinite 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 MovementElectron 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 SpectrumElectromagnetic 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: WavelengthWave-Like Properties: Wavelength• Wavelength: length of wave from two neighboring crest.

• Amplitude: height of wave from origin to crest.

Wave-Like Properties: FrequencyWave-Like Properties: FrequencyFrequency (Hz) : how many waves pass a certain point per second. Hz. =Hertz = (waves/second)

Wave-Like Properties: EnergyWave-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 AnalysisElectromagnetic Spectrum Analysis

• 1

Electromagentic Spectrum Analysis: Check-UpElectromagentic 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 AnalysisElectromagnetic 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 11.13Infinite 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 LabFlame Test LabPurpose: • 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 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 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 11.14Due: • 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 WavelengthColor’s Wavelength•Each color has its own unique wavelength.

Minerals ColorsMinerals 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 EffectDoppler Effect

Doppler EffectDoppler 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 11.18Infinite 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?”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 MovementElectron 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 LightFireworks: 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 StarsElements in Stars• A star is a sphere of super hot gases—mostly hydrogen

and helium. How do we know this?

• Every chemical element has a unique emission spectrum. • Emission spectrums help astronomers identify the

composition of stars.

Hydrogen 69%

Helium29%

Heavier elements 2 %Carbon, Oxygen,Nitrogen, & Calcium