Download Chapters 5.1 and 5.2: A Review – Be sure to Explain your answers

Chapters 5.1 and 5.2: A Review – Be sure to Explain your answers.
ROYGBIV
----------- > frequency↑
wavelength↓
Energy↑
Speed (stays the same)
Blue light has a wavelength of roughly 300 nm, while Orange light has a wavelength of roughly 600 nm.
1. Visible light – such as blue and orange light are examples of what type of radiation?
Electromagnetic Radiation
2. Which color, blue or orange, would have a higher frequency? Explain.
Blue. A wave of blue light has a shorter wavelength, which implies it has a greater frequency.
3. Which color, blue or orange, would have a higher Energy? Explain.
Blue. A wave of blue light has a greater frequency. Frequency relates directly with energy.
So, blue light would have a higher energy.
4. Which color, blue or orange, would have a higher speed? Explain.
They both have the same speed. All electromagnetic waves travel at the speed of light.
5. Name two other types of electromagnetic radiation (waves). Tell if they would be of higher
energy or lower energy than visible light (where blue and orange light waves exist on the
spectrum)
Lower Energy Examples – Radio waves, Microwaves, Infrared
Higher Energy Examples – UV Waves, Gamma Rays, X-rays
6. Below are three crudely drawn Bohr models of the Hydrogen atom.
Ground
Excited
Relaxing
Sketch and then give a written explanation of what will happen when a wave of UV light
excites the electron in the Hydrogen atom. Start by drawing where the electron is initially.
A photon of light enters the atom and excites the electron if it has enough energy to do so.
As a result the electron goes to a higher energy level when it is excited. Then, when it is in
the process of relaxing, it goes back down to a ground state, and for each energy level it
stops at before then, will give off energy in the form of a different photon of light.
7. In class we performed chemical flame tests to observe the effects of thermal or heat energy
on the electrons of different metal salts.
If all you had was two different metal salts and a source of flame, how could you tell the two
different metals apart?
A sample of each metal salt could be added to the flame. If the resulting colors of the flames
are different, then the two metals could be distinguished from each other.
If the colors of the flames are similar, they could be viewed through a diffraction grating or
spectroscope. This would split the color of the flame into its individual wavelengths (this is
an example of an emission spectrum). Since each element has a unique spectrum, the metals
could be determined by the spectrum they give off.
8. Define and explain how the Emission Spectra and Absorption Spectra are related for a
specific element.
Both the emission spectra and absorption spectra are taken from the visible light portion of
the electromagnetic spectra.
The Absorption Spectra of an element contains all of the colors of light readily absorbed by
the electrons of that element. It is shown by a colored background (ROYGBIV) with black
lines representing those colors that belong to the Emission Spectra.
The Emission Spectra of an element contains all the colors of light readily emitted or given
off when the electrons of that element are excited. It is usually shown by a black background
(covering those colors that are absorbed) and single vertical lines of the colors that are
emitted.
Explain how you could use emission spectrums and a spectroscope to determine the type of
gas being observed, if you are exciting a gas in a high voltage light box.
A spectroscope contains a prism that splits the light given off by the energized gas into its
individual wavelengths or colors. These colors can be compared to different emission spectra
for different elements. If one of the emission spectra matches the pattern observed through
the spectroscope that would be the element being observed.
9. Compare and contrast the Bohr Model and the Quantum Model of the Atom in respect to the
following.
a. The Electron (What state is it in? What can be determined about it?)
Bohr Model – Electron is a particle. It’s position and speed can be determined.
Quantum Model – Electron behaves more like a wave. It’s position and speed cannot be
determined at the same time.
b. Energy Levels (How are they defined?)
Bohr Model – Well defined circular orbits surrounding the nucleus.
Quantum Model – Areas of high probability that also surround the nucleus, but are not
circular orbits.
c. Emission / Absorption Spectra (The same or Different?)
Both the Bohr Model and the Quantum Mechanical Model account for the Emission and
Absorption spectra of elements. The Quantum Mechanical Model is the model currently
accepted.