Download Chapter 7 Key

CHM 111
Chapter 7 Worksheet: The Quantum mechanical model of an atom
Name: _________________________________
Q1.
The yellow light given off by a sodium vapor lamp used for public lighting has a wavelength of 589 nm.
(A) What is the frequency of the radiation?
5.09 × 1014 1/s
(B) What is the energy of a photon of this light?
3.37 × 10-19 J
(C) What is the energy of 1.00 mole of photons of this frequency?
203000 J or 203 kJ
Q2.
Arrange the following regions of the electromagnetic spectrum in order of increasing frequency
Microwave, X Rays, Ultraviolet, Visible, Gamma rays
Microwave, Visible, Ultraviolet, X rays, Gamma rays
Q3.
What does it mean when we say that light is quantized?
It exists as a bunch of photons, or individual packets of light. One photon is the smallest amount of light you
can have, and you can’t divide it any further. Light is always a whole number, or quantity, of photons, and fractions are
impossible, so light is “quantized”. (This isn’t quite the normal definition of “quantity”, but no one could come up with a better
word for this idea, so we’re stuck with “quantized”. This is also where the word “quantum” comes from.)
Q4.
What is the difference between a line spectrum and a continuous spectrum?
A continuous spectrum has light of essentially every color and wavelength, without any gaps (put through a
prism, it looks like a full rainbow). A line spectrum contains only a handful of very specific colors or wavelengths, and every
other color is missing; it’s mostly gaps (put through a prism, you might see a narrow slice of blue, a narrow slice of green, and a
couple narrow slices of red, and all the other colors are missing).
Q5.
Give the maximum number of orbitals in an atom that can have these quantum numbers:
(A) n = 3
_____9________
(B) n = 3, l = 1
_____3________
(C) n=2, l=1, ml= 0
_____1_________
(D) n=0, l=0, ml=0
_____0_________
Q6.
Removing the electron from a Hydrogen atom corresponds to a raising the electron from n=1 to an orbit that has n=∞.
What is the energy needed to remove the electron from a hydrogen atom?
2.18 × 10-18 J
What is the energy in terms of kJ per mole?
1310 kJ/mol or 1.31 × 103 kJ/mol
Q7.
The light from a Helium-Neon laser (used to define a meter) has a wavelength of 632.99139822 nm
Calculate the frequency of this laser beam.
4.736 × 1014 1/s
What is the energy of one mole of this radiation?
1.89 × 105 J or 189 kJ
Q8.
Calculate the velocity of an electron that has a de Broglie wavelength of 0.0897 nm.
Mass of an electron = 9.11  10-28 g
8.11 × 106 m/s
Q9.
Circle the sets of quantum numbers that can specify an orbital.
a) n = 3, l = 3, ml = 0
b) n = 1, l = 0, ml = 0
c) n = 5, l = 4, ml = -4
d) n = 2, l = 2, ml = -2
Q10.
One photon of a particular radiation has energy of 6.22  10-19 J.
a) Calculate the frequency of this radiation.
9.39 × 1014 1/s
b) What is the wavelength of this radiation in nm?
320 nm
Q11.
Consider the transition from n = 1 to n = 5 in the Hydrogen atom.
a) Is energy absorbed or emitted in this transition?
absorbed
b) Calculate the energy of the photon that corresponds to this transition.
2.09 × 10−18 J
c)
Calculate the wavelength that corresponds to this transition.
9.49 × 10−8 m or 94.9 nm
Q12.
Circle each of the following orbitals that are real (can exist).
a) 2d
b) 3f
c) 1s
d) 3d
e) 6p
Q13.
The brightest light emitted by the sun has a wavelength of about 0.48 µm.
Calculate the frequency of this radiation.
6.2 × 1014 1/s
What is the energy of one photon of this radiation?
4.14 × 10−19 J
Q14.
Q15.
What is the maximum number of orbitals that are specified by each set of quantum numbers?
a) n=3, l=2, ml = -2
1
b) n=1, l=0
1
c) n=5
25
d) n=2, l=2
0
e) n=5, l=3
7
f) n = 2
4
Arrange the following colors of the visible light in order of increasing wavelength.
Orange, Blue, Green, Violet, Yellow, Red
Violet, Blue, Green, Yellow, Orange, Red
Q16.
An object weighing 0.100 g is travelling at a speed of 45.0 m/s. What is the deBroglie wavelength of this object?
1.47 × 10−31 m