Lesson 5.4 Electromagnetic Radiation and the Bohr Model
star
star
star
star
star
Last updated 12 months ago
20 questions
Required
3
Required
3
Question 1
01:16
keyboard_arrow_down
Required
1
Questions 2 & 3
01:32
keyboard_arrow_down
Required
1
Required
1
Questions 4 & 5
02:15
keyboard_arrow_down
Required
1
Required
1
Question 6
03:26
keyboard_arrow_down
Required
1
Question 7
04:12
keyboard_arrow_down
Required
1
Question 8
05:00
keyboard_arrow_down
Required
3
We concentrated on the visible spectrum in the lab, but most substances can absorb electromagnetic energy from many different parts of the spectrum. Some examples are greenhouse gases like carbon dioxide which absorb infrared and metals which strongly absorb microwaves. The article below explains how Niels Bohr used observations of emission and absorption of light to develop a model of how electrons are arranged in atoms.
1
Required
1
Required
1
Required
1
Required
1
Required
1
Required
1
Required
1
Required
1
Required
1
One of the key features of the Bohr Model is that it predicts that the absorption spectrum and the emission spectrum of an element should have features at the same wavelengths. Because electrons can only make certain jumps between energy levels, each element has a unique pattern of possible jumps. Electrons are allowed to jump in either direction. Electrons jump away from the nucleus when they absorb photons and electrons release photons when they jump back.
For each element, the absorption spectrum matches the emission spectrum. If a wavelength is missing in the absorption spectrum, it is present in the emission spectrum.
Scientists, designers and artists are all interested in developing the blackest possible paint. A truly black paint would be able to convert all visible light to heat energy because it can absorb every wavelength of photons in the visible range. An object covered in truly black paint does not reflect light which creates some interesting visual effects. If you are curious, watch the video below.
The emission spectra of individual carbon atoms looks like this.
When atoms bond to make solids like carbon nanotubes, the pattern of the energy levels in the individual atoms changes which is why solid carbon like coal or carbon nanotubes looks black.
Question 19
19.
When we burn coal or other carbon-rich substances, the energy levels of the carbon atoms are the same as the energy levels of the element. Looking at the emission spectrum, what color would you expect to see from the hot carbon. Be sure to explain your thinking.
Question 20
20.
Carbon atoms bonded together into a solid look black. What does that mean in terms of the pairs of energy levels that are available to an electron in the substance to jump between. Be sure to explain your thinking.
Question 1
1.
Question 2
2.
Question 3
3.
Question 4
4.
Question 5
5.
Question 6
6.
Question 7
7.
Question 8
8.
What are some uses of spectral signatures of molecules? Spectral signature is another name for emission spectrum, so the question is asking what can we find out if we know what wavelengths from the electromagnetic spectrum are absorbed or emitted by different substances?
Question 9
9.
Question 10
10.
Question 11
11.
Question 12
12.
Question 13
13.
Question 14
14.
Question 15
15.
Question 16
16.
Question 17
17.
Question 18
18.
What is electromagnetic radiation?
A form of energy that travels in waves through space
A type of chemical reaction that occurs in space
A physical object that emits heat
A form of matter that takes up space
How do electromagnetic (EM) waves differ from ocean waves?
EM waves move slower than ocean waves
EM waves can travel through the vacuum of space
EM waves cannot transmit energy
EM waves require a medium like water to travel
Electromagnetic waves can affect things with an electrical charge.
True
False
Which of the following best describes the relationship between frequency and wavelength?
As frequency increases, wavelength decreases
As frequency increases, wavelength increases
As frequency decreases, wavelength decreases
Wavelength and frequency are not related
The energy transmitted by an electromagnetic wave is related to ...
frequency but not wavelength
wavelength but not frequency
both frequency and wavelength
neither frequency or wavelength
The chlorophyll molecules in the leaf absorb
only blue light
only green light
only red light
all the wavelengths of visible light except for green
Only some substances have a spectral signature.
True
False
What is the primary reason tungsten is used in light bulb filaments?
It is cheaper than other metals.
It emits every frequency of light, producing white light
It emits every frequency of light, producing white light.
It is non-metallic.
What causes gaseous elements to emit light?
Being heated to high temperatures
Rapid cooling
Having electricity to pass through them
Absorbing sunlight
What is an emission spectrum?
A specific sound emitted by vibrating electrons
A mix of all light colors visible to the human eye
The heat emitted from an atom after it has absorbed light energy.
A unique pattern of light emitted by an element when the atom absorbs energy
What major flaw existed in the planetary model of the atom?
It predicted electrons would emit energy as they circled the nucleus and eventually crash into the nucleus
It could not explain the existence of the atomic nucleus
It required electrons to move at extremely high speeds
It did not describe how protons and neutrons were distributed
An electron closer to nucleus has more energy than an electron far away from the nucleus.
True
False
What does it mean for an electron’s energy levels to be quantized?
Electrons have fixed energy levels with specific energy amounts.
Electrons can occupy any space around the nucleus.
Electrons continuously gain and lose energy.
Electrons exist randomly in an undefined orbit.
What happens when an electron moves to a lower energy level?
It emits a photon of light
It moves farther from the nucleus
It releases protons
It absorbs energy
According to Bohr's Model, what causes the distinct lines in an atomic spectrum?
changes in the kinetic energy of the electrons
the shape of the electron's obit
electrons moving between energy levels
changes in the nucleus of the atom
The energy of an electron in an energy level is
kinetic energy
potential energy
thermal energy
atomic energy
The energy of photons emitted by an element is determined by the
the charge of the nucleus
difference in the energy of the energy levels in the atom
