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Chemistry Marking Period 1 Quarterly Study Guide
Matter And Atomic Structure
Multiple Choice
Identify the letter of the choice that best completes the statement or answers the question.
1.
Which state of matter has a definite volume and takes the shape of its container? Liquid
2.
Which state of matter takes both the shape and volume of its container? Gas
3.
The chemical symbol for iron is Fe
4.
All atoms are ____.
a. positively charged, with the number of protons exceeding the number of electrons
b. negatively charged, with the number of electrons exceeding the number of protons
c. neutral, with the number of protons equaling the number of electrons
d. neutral, with the number of protons equaling the number of electrons, which is equal to the
number of neutrons
5.
The particles that are found in the nucleus of an atom are Protons and Neutrons
6.
What charge is the nucleus of an atom? Positive
7.
What part of the atom is the heaviest? The nucelus
8.
The atomic number of an element is the total number of which particles in the nucleus? Protons
9.
An element has an atomic number of 76. The number of protons and electrons in a neutral atom of the
element are 76 p+ and 76e-
10.
The sum of the protons and neutrons in an atom equals the Mass Number
11.
What does the number 84 in the name krypton-84 represent? The Mass Number
14.
All atoms of the same element have the same number of protons
15.
Isotopes of the same element have different Mass numbers
16.
Isotopes of the same element have different number of neutrons
17.
In which of the following sets is the symbol of the element, the number of protons, and the number of
electrons given correctly?
a. In, 49 protons, 49 electrons
c. Cs, 55 protons, 132.9 electrons
b. Zn, 30 protons, 60 electrons
d. F, 19 protons, 19 electrons
18.
The mass number of an element is equal to the sum of protons and neutrons
Chemistry Marking Period 1 Quarterly Study Guide
19.
Using the periodic table, determine the number of neutrons in
20.
How many protons, electrons, and neutrons does an atom with atomic number 50 and mass number 125
contain? 75 neutrons, 50 protons, 50 electrons
21.
Which of the following statements is NOT true?
a. Atoms of the same element can have different masses.
b. Atoms of isotopes of an element have different numbers of protons.
c. The nucleus of an atom has a positive charge.
d. Atoms are mostly empty space.
22.
If E is the symbol for an element, which two of the following symbols represent isotopes of the same
element?
1. E
2. E
3. E
4. E
a. 1 and 2
b. 3 and 4
O. 7 neutrons
c. 1 and 4
d. 2 and 3
23.
Select the correct symbol for an atom of tritium. (Isotope Hydrogen-3)
a. n
c. H
b. H
d. H
24.
Which of the following sets of symbols represents isotopes of the same element?
a.
c.
M
M
M
J
J
J
b.
L
L
L
d.
Q
Q
Q
25.
How is the number of neutrons in the nucleus of an atom calculated? Subtract the atomic number from the
mass number (Neutrons = mass # - Atomic #)
26.
Which of the following isotopes has the same number of neutrons as phosphorus-31? (P-31 has 16 nuetrons)
a.
c.
P
Si
b.
d.
S
Si
27.
What unit is used to measure weighted average atomic mass? amu
28.
Which of the following equals one atomic mass unit?
a. the mass of one electron
b. the mass of one helium-4 atom
c. the mass of one carbon-12 atom
d. one-twelfth the mass of one carbon-12 atom
Chemistry Marking Period 1 Quarterly Study Guide
29.
Which of the following statements is NOT true? (Electrons equal 1/1840 amu)
a. Protons have a positive charge.
b. Electrons are negatively charged and have a mass of 1 amu.
c. The nucleus of an atom is positively charged.
d. Neutrons are located in the nucleus of an atom.
30.
The atomic mass of an element is the ____.
a. total number of subatomic particles in its nucleus
b. weighted average of the masses of the isotopes of the element
c. total mass of the isotopes of the element
d. average of the mass number and the atomic number for the element
31.
The atomic mass of an element depends upon the mass and relative abundance of each isotope of that
element.
32.
What is the formula for calculating the average atomic mass of isotopes?
[(mass A) (%A)] + [(mass B) (%B)] + ……..= average atomic mass
Chemistry Marking Period 1 Quarterly Study Guide
Short Answer
1.List the number of protons, neutrons, and electrons in
C. Nᵒ = 13-6 = 7, p+ = 6, e- = 6
2. Consider an element Z that has two naturally occurring isotopes with the following percent abundances: the isotope
with a mass number of 19.0 is 55.0% abundant; the isotope with a mass number of 21.0 is 45.0% abundant.
What is the average atomic mass for element Z?
[(mass A) (%A)] + [(mass B) (%B)] = average atomic mass
55.0% = 0.55
45.0% = 0.45
[(19.0) (0.55)] + [(21.0) (0.45)] =
[10.45] + [9.45] =
Average Atomic Mass = 19.9
3.A fictitious element X is composed of 10.0 percent of the isotope
, 20.0 percent of the isotope
of the isotope
. Estimate the atomic mass of element X.
, and 70.0 percent
[(mass A) (%A)] + [(mass B) (%B)] + ……= average atomic mass
[(55) (0.10)] + [(50) (0.20)] + [(57) (0.70)] =
[5.5] + [10] + [39.9] =
Average Atomic Mass = 55.4
4.
Isotope
Mass
Percent abundance
50X
49.85
20.0%
51X
50.94
80.0%
a) The percent abundance and masses of the two isotopes of element X are listed above. Calculate the
atomic mass of the naturally occurring X atom to one decimal place. (4 pts.)
[(mass A) (%A)] + [(mass B) (%B)] + ……= average atomic mass
[(49.85) (0.20)] + [(50.49) (0.80)] =
Chemistry Marking Period 1 Quarterly Study Guide
[9.97] + [40.39] =
Average Atomic Mass = 50.4
b) Explain, in terms of their subatomic particles, how 50X and 51X are similar and how they are different. (2
pts.)
Both isotopes have the same number of protons since they are the same element. Protons never change.
They have a different number of neutrons due to the fact that they have different masses.