Introduction to Atoms

1
Introduction to Atoms
Chapter 11
Preview
CRCT Preparation
2
CRCT Preparation
Chapter 11
1. What principle of electromagnetic force is
depicted in the above diagram of an atom?
A Particles with the same charges have no effect
on each other. B Particles with opposite charges
attract each other. C Electromagnetic force
repels objects from the nucleus. D Protons and
neutrons repel each other because they have the
same charge.
3
CRCT Preparation
Chapter 11
1. What principle of electromagnetic force is
depicted in the above diagram of an atom?
A Particles with the same charges have no effect
on each other. B Particles with opposite charges
attract each other. C Electromagnetic force
repels objects from the nucleus. D Protons and
neutrons repel each other because they have the
same charge.
4
CRCT Preparation
Chapter 11
2. What is the key difference that causes the
atoms of one element to differ from the atoms of
all other elements? A the number of electrons B
the number of isotopes C the number of neutrons D
the number of protons
5
CRCT Preparation
Chapter 11
2. What is the key difference that causes the
atoms of one element to differ from the atoms of
all other elements? A the number of electrons B
the number of isotopes C the number of neutrons D
the number of protons
6
CRCT Preparation
Chapter 11
3. Atom A contains 8 protons and 8 neutrons.
Atom B contains 8 protons and 9 neutrons. Which
of the following statements correctly describes
the two atoms? A They are isotopes. B They are
radioactive. C They are atoms of different
elements. D They have the same mass number.
7
CRCT Preparation
Chapter 11
3. Atom A contains 8 protons and 8 neutrons.
Atom B contains 8 protons and 9 neutrons. Which
of the following statements correctly describes
the two atoms? A They are isotopes. B They are
radioactive. C They are atoms of different
elements. D They have the same mass number.
8
CRCT Preparation
Chapter 11
4. Which of the following pieces of equipment
was J. J. Thomson using when he discovered
electrons? A electron microscope B magnifying
lens C cathode-ray tube D telescope
9
CRCT Preparation
Chapter 11
4. Which of the following pieces of equipment
was J. J. Thomson using when he discovered
electrons? A electron microscope B magnifying
lens C cathode-ray tube D telescope
10
CRCT Preparation
Chapter 11
5. Which of the following statements about the
mass of a neutron is true? A A neutron has half
the mass of a proton. B A neutron is a little
more massive than a proton. C A neutron has the
same mass as an electron. D A neutron is a little
less massive than an electron.
11
CRCT Preparation
Chapter 11
5. Which of the following statements about the
mass of a neutron is true? A A neutron has half
the mass of a proton. B A neutron is a little
more massive than a proton. C A neutron has the
same mass as an electron. D A neutron is a little
less massive than an electron.
12
CRCT Preparation
Chapter 11
6. A neutral atom has an atomic number of 20 and
a mass number of 42. How many electrons does the
atom have? A 20 B 22 C 42 D 62
13
Chapter 11
CRCT Preparation
6. A neutral atom has an atomic number of 20 and
a mass number of 42. How many electrons does the
atom have? A 20 B 22 C 42 D 62
14
Chapter 11
CRCT Preparation
7. According to the table, which of the
following sets of particles has no charge? A 6
protons, 5 neutrons, 4 electrons B 5 protons, 6
neutrons, 5 electrons C 4 protons, 4 neutrons, 6
electrons D 6 protons, 5 neutrons, 5 electrons
15
Chapter 11
CRCT Preparation
7. According to the table, which of the
following sets of particles has no charge? A 6
protons, 5 neutrons, 4 electrons B 5 protons, 6
neutrons, 5 electrons C 4 protons, 4 neutrons, 6
electrons D 6 protons, 5 neutrons, 5 electrons
16
Chapter 11
CRCT Preparation
8. According to the table, about how much mass
would a nucleus that is composed of 15 protons
and 18 neutrons have? A 15 amu B 18 amu C 23
amu D 33 amu
17
Chapter 11
CRCT Preparation
8. According to the table, about how much mass
would a nucleus that is composed of 15 protons
and 18 neutrons have? A 15 amu B 18 amu C 23
amu D 33 amu
18
CRCT Preparation
Chapter 11
9. According to the table, which of the
following statements about the mass of subatomic
particles is true? A The particles found in the
nucleus are much more massive than the particles
found in the electron cloud. B Protons and
electrons have about the same mass. C Neutrons
are much less massive than protons and
electrons. D The positively-charged particles in
the nucleus are much more massive than the
neutral particles in the nucleus.
19
CRCT Preparation
Chapter 11
9. According to the table, which of the
following statements about the mass of subatomic
particles is true? A The particles found in the
nucleus are much more massive than the particles
found in the electron cloud. B Protons and
electrons have about the same mass. C Neutrons
are much less massive than protons and
electrons. D The positively-charged particles in
the nucleus are much more massive than the
neutral particles in the nucleus.
20
CRCT Preparation
Chapter 11
10. What would an atom of aluminum that has 13
protons and 15 neutrons be named? A aluminum-13 B
aluminum-15 C aluminum-26 D aluminum-28
21
CRCT Preparation
Chapter 11
10. What would an atom of aluminum that has 13
protons and 15 neutrons be named? A aluminum-13 B
aluminum-15 C aluminum-26 D aluminum-28
22
CRCT Preparation
Chapter 11
11. Oxygen has an atomic number of 8. Which of
the following could form the nucleus of an
isotope of oxygen? A 4 protons and 4 neutrons B
6 protons and 8 neutrons C 8 protons and 10
neutrons D 6 protons and 2 neutrons
23
CRCT Preparation
Chapter 11
11. Oxygen has an atomic number of 8. Which of
the following could form the nucleus of an
isotope of oxygen? A 4 protons and 4 neutrons B
6 protons and 8 neutrons C 8 protons and 10
neutrons D 6 protons and 2 neutrons
24
CRCT Preparation
Chapter 11
12. John Dalton, a British chemist, published
his atomic theory in 1803. What were the three
main points of Daltons theory? Which of those
points were eventually shown to be incorrect?
25
CRCT Preparation
Chapter 11
12. Answer - Full-credit answers should include
the following points All substances are made
of atoms. Atoms are small particles that cannot
be created, divided, or destroyed. Atoms of the
same element are exactly alike, and atoms of
different elements are different. Atoms join
with other atoms to make new substances. The
idea that atoms cannot be divided was shown to be
incorrect when subatomic particles were
discovered. Atoms can also be created or
destroyed during nuclear changes. The idea that
atoms of the same element are exactly alike was
shown to be incorrect. Isotopes of an element
have different numbers of neutrons in them.
26
CRCT Preparation
Chapter 11
13. The interactions of four fundamental forces
can describe all the physical relationships in
nature. Describe these four forces and explain
how they contribute to the structure of an atom.
27
CRCT Preparation
Chapter 11
13. Answer - Full-credit answers should include
the following points Gravitational force is a
force of attraction between objects because of
their masses. A small gravitational force pulls
the particles of an atom together.
Electromagnetic force is a force between charged
objects. Protons and electrons are attracted to
each other because they have opposite charges.
The electromagnetic force holds the electrons
around the nucleus and repels protons from one
another. The strong force is a force that holds
the particles in nuclei together. Without the
strong force, the protons in a nucleus would fly
apart because of the electromagnetic force. The
weak nuclear force is an important force in
radioactive atoms. The weak force plays a key
role in the change of a neutron into a proton and
an electron.