Modern Atomic Theory
Study Guide – Part 1
Electromagnetic Spectrum
1. Classify as always true (AT), sometimes true (ST) or never true (NT).
a. Electrons must have a certain amount of minimum energy, called quantum energy, to
move from one energy level to a higher energy level.
b. Electromagnetic radiation such as x-rays, visible light and radio waves all travel at the
same speed, the speed of light.
2. List the following from lowest to highest frequency:
x-rays, gamma rays, visible light, radio waves, infrared waves
3. Use the following equations to answer the questions that follow. Show your work, proper
dimensional analysis and units.
E= h ν
E = energy of the wave, h = planks constant = 6.626x10-34J*s, ν = frequency
c=λν
c = speed of light = 3.00 x 108 m/s, ν = frequency, λ = wavelength
1.00 nanometer (nm) = 1.00 x 10-9 m
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Violet: 400-430 nm
Indigo: 430-450 nm
Blue: 450-500 nm
Green: 500-570 nm
Yellow: 570-590 nm
Orange: 590-610 nm
Red: 610-700 nm
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a. A wave has a frequency of 22 s-1. Find its wavelength.
b. What is the frequency of a wave if its wavelength is 3.6 nm?
c. As you move across the continuous visible spectrum from red to violet, what happens
to…
Wavelength?
Frequency?
d. A beam of microwaves has a frequency of 1.0 x 109 s-1. A radar beam has a frequency of
5 x 1011 s-1. Which type of radiation…
Has the longer wavelength?
Is nearer to visible light in the EM spectrum?
Is closer to X-rays in frequency value?
e. A bright line spectrum contains a line with a wavelength of 518 nm. Determine…
The wavelength, in meters
The frequency
The energy
The color of the line
2
Emission Spectra
4. Use labeled diagrams to explain why a green color is observed when a sample of copper
nitrate is burned in a flame, but a sample of sodium nitrate produces an orange flame.
Include the following terms in your explanation:
ground state, excited state, quantized, photon, emission spectrum
5. Explain why the line spectrum of hydrogen contains 4 lines in the visible region even though
hydrogen has only one electron.
6. Explain why the line spectrums of hydrogen and helium are different. Are there any
elements that produce same line spectrum?
7. What is the difference between a continuous spectrum and a line spectrum?
a. Name one source that emits a continuous spectrum.
b. Name one source that emits a line spectrum.
c. True or false: Both continuous and line spectra only contain photons in the visible region
of the electromagnetic spectrum.
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Models of the Atom
1. Explain the difference between the Rutherford and Bohr models of the atom.
2. Explain how experimental evidence led to the development of the Bohr model of the atom.
3. Why was the Bohr model ultimately discredited?
4
Vocabulary
Be sure you are able to define the following vocabulary words.
Valance electrons:
Orbital:
Electron configuration:
Aufbau Principle:
Pauli Exclusion Principle:
Hund’s Rule:
Principal energy level:
Metals:
Metalloids:
Non-metals:
Atomic size (radius):
Ionization energy:
Electron affinity:
Electronegativity:
5
Electron Configurations
1. Fill in the following table about the different types of orbitals.
Orbital
sublevel
s orbital
Number of
orbital types
Maximum # of electrons
orbital can hold
Location on the periodic table
p orbital
d orbital
f orbital
2. What are the three rules for filling in the orbitals for electron configurations?
3. Identify the following elements from their orbital (box) diagrams and list the number of
unpaired electrons.
a.
1s
(↑↓)
2s
(↑↓)
2p
(↑↓)(↑ )(↑ )
b.
1s
(↑↓)
2s
(↑↓)
2p
(↑↓)(↑↓)(↑↓)
c.
1s
(↑↓)
2s
(↑↓)
d.
1s
(↑↓)
2s
(↑↓)
3s
( )
3p
( )( )( )
4s
( )
3d
( )( )( )( )( )
3s
(↑↓)
3p
( )( )( )
4s
( )
3d
( )( )( )( )( )
2p
(↑↓)(↑↓)(↑↓)
3s
(↑↓)
3p
(↑↓)( ↑↓)(↑↓)
4s
(↑↓)
3d
(↑↓)( ↑↓)( ↑↓)( ↑ )( ↑ )
2p
(↑↓)(↑↓)(↑↓)
3s
(↑↓)
3p
(↑↓)( ↑↓)(↑↓)
4s
(↑↓)
3d
(↑↓)( ↑↓)( ↑↓)( ↑↓)( ↑↓)
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4. What is a valence electron? How many maximum valence electrons can an atom hold in
each period?
5. Write the full electron configuration for the following elements and circle the valence
electrons.
Element
Atomic
number
Electron configuration
Full
Noble gas
shorthand
Be
6
1s22s22p4
F
10
1s22s22p63s23p2
Cl
19
1s22s22p63s23p64s23d5
Xe
85
6. Indicate if the following electron configurations are possible or not. If it is possible, identify
the atom. If not, explain why.
a.
b.
c.
d.
e.
f.
g.
1s22s22p3
1s22s22p63s23p5
1s22s22p103s23p1
1s22s22p63s23p64s23d5
[Kr]5s24d7
[[Ne]3s23d103p3
[Rn]7s25f6
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Periodic Trends
7. Fill in the table below with the number of valence electrons for each of the 8 groups on the
periodic table.
Group
Number
I
II
III
IV
V
VI
VII
VIII
Group name
# of valence
electrons
Alkali
metals
1
Electron configuration of valence
orbital ONLY
(n) s1
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8. Be able to describe and explain the following periodic trends:
a. Atomic radius
b. Ionization energy
c. Electron affinity
d. Electronegativity
9. Use the following sets of elements to complete the questions below.
i. Ba, Ca, Ra
ii. P, Si, Al
iii. Rb, Cs, K
a. List the 3 elements in order from the largest to the smallest atomic radius.
i.
ii.
iii.
b. List the 3 elements in order from the highest to lowest ionization energies.
i.
ii.
iii.
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Metal,
metalloid or
non-metal
metal