Multiple choice
1. A sample of salt water, NaCl (aq) can be described as: (Circle all that apply) (3)
a.) a mixture
b.) a solution
c.) heterogenous
d.) an element
e.) homogenous
2. (100.50 cm) x (23.0 m s-2) x (4.0 kg)
a. 9246
𝑘𝑔 𝑚2
𝑠2
b. 92.46
c. 90
𝑘𝑔 𝑚2
𝑠2
d) 92
(3)
𝑘𝑔 𝑚2
𝑠2
e) 9.2 x 103
𝑘𝑔 𝑐𝑚 𝑚
𝑠2
𝑘𝑔 𝑚2
𝑠2
3. Density is an intensive property of a material that is useful for which of the following tasks: (3)
a.) Interchanging between the mass of a material and the volume of space in which it occupies
b.) Interchanging between volume of space occupied by a material and its mass
c.) Calculating the mass of a fluid from a known capacity
d.) All the above
4. A thermometer is considered accurate if its error is less than 1%. Over three experimental trials, a
certain brand of thermometer reports the boiling temperature of water as 100.7oC, 100.7oC, and
100.9oC. This thermometer is: (3)
a.) accurate
d.) accurate, but not precise
b.) precise
e.) precise, but not accurate
c.) neither
f.) both
5. The product of magnesium and nitrogen would be:
(3)
a.) MgN magnesium nitride
d.) Mg3N2 magnesium nitride
b.) Mg2N magnesium nitride
e.) Mg2N3 magnesium nitride
c.) Mg3N2 trimagnesium dinitride
6. Chemical reactivity is dictated by: (1)
a.) protons
c.) valence electrons
b.) neutrons
d.) core electrons
7. Which has the largest ionic radius? (2)
a.) W6+
d.) Na+
b.) F
e.) O2-
c.) S2-
The diagram to the right shows different processes induced in a hydrogen atom by electromagnetic
radiation. Use the diagram to answer questions 8 and 9.
8. Which of the following are true about process B ? (3)
a.) The photon emitted from this process has a shorter wavelength than process C
b.) The photon emitted from this process has a lower
frequency than process C
c.) The energy of the photon emitted from this process
has a lower energy than process C
d.) Both a.) and b.) are true
n=4
A
B
Energy
C
D
n=3
n=2
e.) Both b.) and c.) are true
9. Select all true statements below. (3)
n=1
a.) In process A, a photon is absorbed which promotes H
to its 4th excited state.
b.) The photon absorbed in process D has a longer wavelength than the photon absorbed in process A
c.) The energy in during process D is exactly equal to the energy out in process B
10. Which of the following sets of quantum numbers does NOT represent a possible ground state
electron of Cd: (3)
a) 5, 1, 1, ½
b) 5, 2, 1, ½
c) 4, 0, 0, - ½
d) 2, 1, -1, - ½
e) 3, 2, -2, ½
Short Answer
11. Using quantum numbers, determine the maximum possible number of electrons a carbon atom can
accomodate. (5)
12. Why do metals exhibit line spectra? In other words, why can metals emit only specific wavelengths
of light?
(4)
13. What is an orbital?
(3)
14. Why does the Bohr model fail?
(3)
15. Write a balanced reaction for the product of magnesium metal and nitrogen gas. Then, using
electron configurations, show the electron transfer process leading to the formation of the product.
Finally, draw the lewis dot structure of the product and name it.
(8)
Calculations
16. Fill in the missing values.
(10)
Isotope
Isotopic mass (amu)
24
12𝑀𝑔
23.985 041
25
12𝑀𝑔
24.985 837
26
12𝑀𝑔
25.982 593
% Abundance
10.00
17. Given below is a table of ionization energies (in aJ) for an unknown element, X.
I1
1.4
I2
2.7
I3
3.9
I4
56.1
I5
58.7
I6
62.6
a.)
What group does this element belong to? Explain your answer. (5)
b.)
What is the energy needed to form 10 X3+ ions? (5)
I7
78.1
I8
89.3
18. A laser beam emits 5 x1016 photons per second. If the laser is set to operate at 14 mJ/sec,
determine the wavelength of the photons in the beam (in nm). (10)
𝑚
19. A single 500 nm photon strikes a metallic surface. An electron is ejected with a velocity of 106 𝑠 .
Determine the threshold frequency of the metal. (20)
Bonus
%error = | avg – true | ÷ true
1. What is the electron configuration of Fe+? (1)
νλ = c
E = nhν
2. What is the electron configuration of the 2nd
excited state of Ar? (2)
Ekinetic = Ephoton – Ethreshold
1 ̅̅̅2
̅
Ekinetic = 2 𝑚𝑉
3. Name this molecule: WN2 (2)
Avg atomic mass = Σ (isotope mass)(abundance)
mass of electron = 9.109 x 10-31 kg
h = 6.626 x 10-34 Js
4. Refer back to the ionization energy table in problem 17. Using that data along with the data tables
below, calculate the energy of reaction to form X2O3. The radii provided below are in pm. Assume an
ionic radius of 100 pm for X3+. (10)