Chapter 4:
Structure of the Atom
Practice Test
1.
Before the 19
th
century, most scientists had no evidence that anything smaller than an atom existed. Who's work led to the discovery of a particle smaller than an atom?
a.
Ernest Rutherford
b.
Henri Becquerel
d.
All of the above.
Hint
2.
Becquerel observations of uranium compounds led him to conclude he had evidence for the existence of a light, negatively charged particle that was even smaller than an atom. What form of radiation was Becquerel dealing with?
a.
gamma rays
b.
beta particles
c.
X-ray
d.
alpha particles
Hint
3.
In the electron cloud model of the atom, what does the electron cloud represent?
a.
a cloud of many tiny electrons surrounding an atom
b.
a cloud of electrons scattered throughout a positively charged nucleus
c.
the probable location of electrons within an atom
d.
layered clouds of electrons resembling a tiny atmosphere within an atom
Hint
4.
Rutherford's alpha particle experiment with gold foil demonstrated the existence of what part of the atom?
a.
the nucleus
b.
electrons
c.
neutrons
d.
energy levels of electrons
Hint
5.
Rutherford noticed that an alpha particle has twice the charge, but four times the mass of a hydrogen atom; that is there were two extra units of mass and no additional charge. What causes the extra mass?
a.
neutrons
b.
electrons
c.
quarks
d.
heavier protons in alpha particles
Hint
6.
What distinguishes atoms of different elements?
a.
number of protons in an element's nucleus
b.
number of neutrons
c.
number of electrons
d.
number of protons plus neutrons
Hint
7.
Which type of radiation might penetrate a thick sheet of paper, but be stopped by a sheet of aluminum foil?
a.
beta
b.
alpha
c.
X-rays
d.
gamma
Hint
8.
What is radioactivity?
a.
the transfer of energy by electromagnetic waves
b.
the release of high-energy particles by radioactive elements
c.
energy released by the transfer of electrons between different energy levels
d.
All of the above.
Hint
9.
What model did Niels Bohr have of the atom?
a.
electrons moving in a fixed orbit around a nucleus
b.
a nucleus surrounded by an electron cloud
c.
a solid mass with electrons scattered through it
d.
a solid indivisible particle
Hint
10.
How do scientists know there are different energy levels of electrons?
a.
It takes differing amounts of energy to remove electrons from an atom.
b.
Different electrons have different charges.
c.
Scientists can describe the exact locations of electrons and determine their energy.
d.
All of the above.
Hint
11.
Henri Becquerel observed that a sample of uranium could affect photographic plates even when the plates were wrapped in paper and placed into a drawer. What natural phenomenon was Becquerel observing?
a.
radioactivity
b.
electromagnetism
c.
neutrons
d.
X-rays
Hint
12.
What model did John Dalton have of the atom?
a.
a solid mass with electrons scattered through it
b.
a nucleus surrounded by an electron cloud
c.
electrons moving in a fixed orbit around a nucleus
d.
a solid indivisible particle
Hint
13.
Rutherford's experiments led him to conclude that the nucleus of an atom contains small particles. What name did Rutherford give to these particles?
a.
neutrons
b.
protons
c.
positrons
d.
alpha particles
Hint
14.
In an experiment with a Crooke's Vacuum tube, J. J. Thompson observed that a beam of particles was deflected when it passed through an electric field. What particles did Thompson observe?
a.
protons
b.
electrons
c.
atoms
d.
neutrons
Hint
15.
Radon is a dangerous radioactive gas that can find its way into peoples' homes. What is the source of radon?
a.
It is produced by the decay of rocks containing thorium and uranium.
b.
It is produced high in the atmosphere by reacting sunlight and oxygen.
c.
It is produced in cathode ray tubes.
d.
It is produced when airborne sulfate and nitrate dissolve into rainwater.
Hint
