Medway High School
Name_________________
Accel Chemistry
Chemistry Chp 4 Practice TEST
11) He was the first scientist that proposed the atom has a nucleus with protons; electrons
outside the nucleus; and the atom is mainly empty space
a) Democritus
b) Dalton
c) Rutherford d) Cathodus
12) Which of these statements is false?
a) electrons have a negative charge
b) the atomic number equals the number of neutrons
c) the nucleus of an atom is positively charged
d) electrons have a mass much less than 1 amu
19) Which of the following discoveries was made using the Cathode Ray Tube?
a) proton
b) neutron
c) electron
d) all of these
20) Rutherford’s Gold foil experiment led to which theory?
a) plum pudding model
b) discovery of the proton
c) discovery of the electron
d) The nucleus in the center and electrons in the outer space
13) The mass number equals the:
a) sum of protons and neutrons
b) sum of protons and electrons
c) sum of protons, neutrons, and electrons
d) atomic weight minus atomic number
15) Which of these statements is true?
a) Chromium-51 has 27 protons and 24 neutrons in its nucleus
b) Cobalt-59 has 29 protons and 30 neutrons in its nucleus
c) Uranium-238 is the most common naturally occurring isotope of Uranium
d) Hydrogen-3 has 2 protons and 1 neutron in its nucleus
16) An atom of an element with mass number 178 and atomic number 72 contains:
a) 178 protons, 178 electrons and 106 neutrons
b) 106 protons, 106 electrons and 72 neutrons
c) 72 protons, 72 electrons and 106 neutrons
d) 106 protons, 106 electrons and 72 neutrons
17) How do the isotopes of Carbon-12 and Carbon-14 differ?
a) Carbon-14 has a different atomic number
b) Carbon-14 has two more protons Carbon-12
c) Carbon-14 has two more electrons Carbon-12
d) Carbon-14 has two more neutrons than Carbon-12
18) The number 12 in the name Carbon-12 represents:
a) the atomic number
b) the mass number
c) the number of neutrons
d) the number of neutrons
Mr. Hoek
1 of 5
October 16, 2012
Medway High School
Name_________________
Accel Chemistry
There are five naturally occurring isotopes of the unknown atom X. The relative
abundance and mass of each are as follows. Calculate the Atomic Mass and identify of
atom X.
Element
64
X
66
X
67
X
68
X
70
X
Mass Number
63.929 amu
65.926 amu
66.927 amu
67.925 amu
69.925 amu
Abundance
48.89 %
????? %
4.11 %
18.57 %
0.62 %
27) What is the value of the unknown % abundance (above)
100%-48.89%-4.11%-18.57%-0.62%= 27.81%
28) What is the Atomic Weight ______65.4_____________
29) What is the Identity of atom X _____Zinc_____________
(34)What is an atom?
See class notes there are 30 things to explain an atom
(36)With which of these statements would John Dalton have agreed in the early 1800s?
For each, explain why or why not.
a. Atoms are the smallest particles of matter.
b. The mass of an iron atom is different from the mass of a copper atom.
Dalton did not know masses of atoms
c. Every atom of silver is identical to every other atom of silver.
d. No, He stated that a compound is composed of atoms of two or more different
elements with the same relative whole number ratio.
Mr. Hoek
2 of 5
October 16, 2012
Medway High School
Name_________________
Accel Chemistry
Structure of the Nuclear Atom
(38)What experimental evidence did Thomson have for each statement?
a. Electrons have a negative charge.Hint the beam was repelled by the negative and
attracted to the positive electrode
b. Atoms of all elements contain electrons.Hint performed the above experiment
with many different gases
(39)Would you expect two electrons to attract or repel each other?
repel
(40)How do the charge and mass of a neutron compare to the charge and mass of a
proton?
neutron mass = 1 a.m.u. no charge proton mass = 1 a.m.u. positive charge
(41)Why does it make sense that if an atom loses electrons, it is left with a positive
charge?
When electrons leave the atom they leave behind an atom with more
protons than electrons. Since protons are positively charged, more protons than electrons
would produce a positively charged atom (cation)
(42)Describe the location of the electrons in Thomson’s “plum pudding” model of the
atom.
The electrons are scattered throughout the atom
(43)How did the results of Rutherford’s gold-foil experiment differ from his
expectations?
Rutherford expected the positively charged alpha particles to either
go straight through the gold foil or possibly get stuck in the gold foil. Instead he found
Mr. Hoek
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October 16, 2012
Medway High School
Name_________________
Accel Chemistry
that the alpha particles mainly went straight through the foil with some coming off at
various different angles. Some even came virtually straight back, like a bullet (or cannon
shell) being shot at a tissue and ricocheting off.
(44)What is the charge, positive or negative, of the nucleus of every atom?
(45)In the Rutherford atomic model, which subatomic particles are located in the
nucleus?
positively charged particles = protons
Distinguishing Among Atoms
(46)Why is an atom electrically neutral?
an atom has equal # of electrons
(negative charge) to # of protons (positive charge)
(47)What does the atomic number of each atom represent?
the number of protons
(48)How many protons are in the nuclei of the following atoms?
a.
b.
c.
d.
e.
f.
Phosphorus
Molybdenum
Aluminum
Cadmium
Chromium
Lead
15
42
13
48
24
82
(49)What is the difference between the mass number and the atomic number of an
atom?
mass # = #p+ + #no as well as the mass of a specific isotope of an atom
Atomic # = the number of protons in the nucleus
(51)Name two ways that isotopes of an element differ.
the # of neutrons in the
atom and its mass#
(52)How can there be more than 1000 different atoms when there are only about 100
different elements?
Mr. Hoek
there are different number of isotopes for each atom
4 of 5
October 16, 2012
Medway High School
Name_________________
(55)What is the atomic mass of an element?
Accel Chemistry
the mass of the atom found on the
periodic table. Its weighted average mass of all the isotopes found in nature
(56)How are the elements arranged in the modern periodic table?
by the atomic
number
Mr. Hoek
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October 16, 2012