CH 115 Fall 2014
Mock Exam 1
Multiple Choice
1. Which of the following represents an invalid set of quantum numbers?
a). (15, 3, 0, ½)
b). (1, 1, 0, -1/2)
c). (4, 3, -1, ½)
d). (2, 1, -1, -1/2)
2. The energy of a photon of light is halved. What will happen to the wavelength and
the frequency of this light, respectively?
a). halved, halved
b). quadrupled, halved
c). doubled, halved
d). halved, doubled
3. How many protons, neutrons, and electrons (respectively) are present in 160Au?
a). 79, 81, 79
b). 81, 79, 81
c). 80, 80, 80
d). 79, 81, 81
4. Which of the following is not an expected common monatomic ion?
a). O2b). N3+
c). Na1+
d). Se25. Which of the following represents the ground-state electron configuration for the
neutral atom Zr?
a). 1s22s22p63s23p64s24d104p65s25d2
b). 1s22s22p63s23p64s23d104p6
c). 1s22s22p63s23p64s23d104p65s24d2
d). 1s22s22p63s23p64s23d104p65s14d3
6. Select all of the atoms that have the same number of neutrons.
37Cl and 40Ca
I.
42Sc and 43Ti
II.
41Sc and 39K
III.
a). I only
b). II only
c). I and II only
d). I and III only
e). I, II, and III
CH 115 Fall 2014
Mock Exam 1
7. Which of the following contains a halogen, an alkali metal, and a metalloid in that
order?
a). Kr, Na, B
b). Br, Cs, Si
c). Cl, Ba, Zn
d). F, Be, Si
8. What is the formula for the ionic compound that forms between barium and
chloride? OMIT
a). Ba2Cl
b). BaCl
c). Ba2Cl2
d). BaCl2
9. Indicate the correct set of four quantum numbers for the electron of highest energy
in the ground-state configuration of Na.
a). (2, 1, 1, -1/2)
b). (3, 1, 0, ½)
c). (3, 0, 0, ½)
d). (3, 1, 1, ½)
10. What is the correct name for CCl4?
a). carbon tetrachloride
b). carbon (IV) chloride
c). monocarbon tetrachloride
d). carbon chlorate
11. Which of the following elements does not have 5 valence electrons?
a). As
b). B
c). N
d). Sb
12. The atomic weight of copper is 63.55 amu. In a sample of the element, 69.17% of
copper is present as Cu-63 with an atomic mass of 62.939 amu. What is the atomic
mass of the other isotope and how many neutrons does it contain?
a). 64.92 amu, 29 neutrons
b). 64.92 amu; 36 neutrons
c). 45.9 amu; 17 neutrons
d). 63.55 amu; 36 neutrons
13. Select the correct noble gas electron configuration for molybdenum (Mo).
a). [Kr]5s24d4
b). [Xe]5s24d4
c). [Xe]5s14d5
CH 115 Fall 2014
Mock Exam 1
d). [Kr]5s14d5
14. Order the following elements from highest to lowest ionization energy: Sr, Be, Mg,
Ca, Ba.
a). Ba, Sr, Ca, Mg, Be
b). Be, Mg, Ca, Sr, Ba
c). Be, Ca, Sr, Mg, Ba
d). Be, Mg, Ca, Ba, Sr
15. Which of the following elements has the largest atomic radii?
a). N
b). B
c). Li
d). F
16. Which ion has the largest radius?
a). Li+
b). Na+
c). Mg2+
d). Al3+
17. Which of the following statements are true?
I.
Each set of d orbitals contains 7 orbitals.
II.
Each set of d orbitals can hold a maximum of 14 electrons.
III.
The first energy level contains only s and p orbitals.
IV.
The s orbital in any shell is always spherically symmetrical.
a). I and II only
b). I, III, and IV only
c). IV only
d). III only
18. In another universe, element X has 3 naturally occurring isotopes: 100X, 102X, and
105X. If the atomic weight of X is 100.73 amu, which isotope has the highest natural
abundance?
a). 100X
b). 102X
c). 105X
d). It cannot be determined from the information given.
19. Consider two electron transitions. In the first case, an electron falls from n=4 to n=2,
giving off a photon of light with a wavelength equal to 488 nm. In the second
transition, an electron moved from n=3 to n=4. For this transition, we would expect
that:
a). energy is emitted, and the wavelength of the corresponding photon will be
shorter than the first transition
CH 115 Fall 2014
Mock Exam 1
b). energy is emitted, and the wavelength of the corresponding photon will be
longer than the first transition
c). energy is absorbed, and the wavelength of the corresponding photon will be
shorter than the first transition
d). energy is absorbed, and the wavelength of the corresponding photon will be
longer than the first transition
Short Answer
20. The atomic weight of boron is 10.8 amu. Assume that boron has two isotopes: 10B
and 11B. Sketch a drawing of what the mass spectrum chart for boron would look
like. What are the percent abundances of the two isotopes? Why is the atomic
weight for boron (and most other elements) not a whole number value?
We need calculate the percent abundances for the isotopes first before we can
draw the mass spectrum chart. You can assume the mass numbers given for
each isotope are approximately equal to the atomic mass value that we need
to put into the atomic weight equation.
AW = (x)(10 amu)+ (1-x)(11 amu)  weighted average of our isotopes
10.8 = 10x + 11 – 11x distribute and combine like terms
-.2 = -x  subtract 11 from both sides
x = .2  1-x = .8
20% of 10B and 80% of 11B
Now we can use these percentages to construct our mass spectrum chart.
Atomic weight is generally not a whole number value because it is a weighted
average that takes into account the relative abundances of each of the indivual
isotopes.
CH 115 Fall 2014
21. Complete the table below.
Name
Nitrogen trioxide
Sulfur tetrachloride
Mock Exam 1
Formula
NO3
Ionic or Molecular?
molecular
SCl4
molecular
22. Draw the Lewis structures for the following molecules and predict how many
double bonds will be expected for each.
a). NO3b). NF3