Chemistry and the Electromagnetic Spectrum

Today's LO: You will be able to describe the relationship between energy, frequency, and wavelength

Get out your packet. You will fill in the notes on page 15.

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You also have information 9 and 10. ​

Wave Notes

Today's LO: You will be able to describe the relationship between energy, frequency, and wavelength

​long wavelength, low energy, low frequency

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short wavelength, high energy, high frequency​

Today's LO: You will be able to describe the relationship between energy, frequency, and wavelength

Wavelength has an inverse relationship to frequency and energy.

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As wavelength increases frequency and energy will decrease.

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All waves move at the speed of light ( 3.00 x 10^-8 m/s​)

Parts of the wave

Multiple Choice

How is wavelength related to frequency?

• wavelength has a direct relationship to frequency

• wavelength is the same as frequency

• wavelength has an inverse relationship to frequency.

When the electron returns ​to the lowest energy level it is at its ground state

Why do some metals produce color?

​Ground State

Excited State

When the electron returns ​to the lowest energy level it is at its ground state

Application of the Flame Test

Multiple Choice

What is the lowest possible energy level that an electron can occupy?

• Excited state

• Fundamental state

• Ground state

• Outermost state

Visible light is only a small part of the electromagnetic spectrum. We cannot feel or see most wave types. Reds have the least amount of energy, so they have the longest wavelengths.

Visible Light

Waves that have the longest wavelength are made with the most energy and have more frequency. All waves on the spectrum travel at the same speed - the speed of light which is 3.00x10^-8 m/s.

Multiple Choice

Which of the following visible colors has the shortest Wavelength?

• Purple

• Green

• Yellow

• Red

Multiple Choice

Number 1 represents the

• Wavelength (corresponds to rate/frequency of the wave)

• Amplitude (corresponds to energy/volume)

• the frequency

Multiple Choice

Which of the following visible colors has the longest Wavelength?

• Purple

• Green

• Yellow

• Red

Multiple Choice

Which wavelength can humans see?

• Microwaves

• Radio waves

• Visible light

• Gamma rays

Multiple Choice

Which has the LONGEST wavelength and, therefore, the lowest frequency/energy

• Gamma Rays
• Radio Waves
• Visible Light
• Infrared rays

Multiple Choice

Which has the SHORTEST wavelength and, therefore, the highest frequency/most energy

• Radio waves
• Ultraviolet Rays
• Gamma Rays
• X-rays

Multiple Choice

All electromagnetic waves have the same...

• frequency
• speed
• wavelength
• energy

Emission spectrums are how we know what is all over the universe. Through telescopes and sophisticated instruments we can collect these emission spectrums and find the compositions of other stars, nebulas, and comets.

These spectra are unique to each element, so we can identify the elements present. ​

Atom's "fingerprints"​

​Emission Spectrums

Some text here about the topic of discussion

Multiple Choice

Why are line emission spectra of elements called "atomic fingerprints"?

• They are all the same
• They are all unique
• They are all similar
• They all contain colored light

Multiple Choice

The unknown emissions spectra belongs to the element

• Hydrogen

• Mercury

• Neon

• Sodium

1. You should finish pages 11-13 in your packet

2. Work on homework, study, or read for the remainder of the period (this is a good time to make up missing assignments)

There is additional practice on the last page of your packet.

Multiple Choice

What gases are in the unknown mixture?

• Gas B & Gas D
• Gas C & Gas B
• Gas A & Gas D
• Gas D & Gas C

Multiple Choice

The unknown emissions spectra belongs to the element

• Hydrogen

• Mercury

• Neon

• Sodium

You have the equations for calculating energy, frequency, and wavelength in your reference charts.

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I have included a couple of videos if you need help figuring out how to use these equations. ​

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Calculating frequency and wavelength. ​

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Fill in the Blanks

What is the wavelength of a wave that has a frequency of 5.2x10^-9 Hz?

Use your reference chart to find the answer to this question.

Write your answer to the hundredths place (3 significant figures). Do not put units.

Multiple Choice

A particular nuclear process releases a single gamma ray photon with an energy of 4.75x10^-14 joules. What is the frequency of this radiation?

 

f =  E/h                                           h= 6.63 x 10-34 J*s

• 1.43 x 10^-5 Hz

• 7.17 x 10¹⁹ Hz

• 1.39 x 10^-20 Hz

• 2.15 x 10²⁸ Hz