Indiana Science Grade 8

Chapter 3: Inside the Atom

Inside the Atom

1.
Elements created by artificial transmutations are called __________.
A)synthetic elements
B)alpha products
C)degraded elements
D)isotopes
2.
Why did Thomson include some positively charged matter in his model of the atom?
A)If atoms contained only electrons and empty space, then alpha particles should bounce right off them and never pass through.
B)If atoms contained only negative charges, all matter would be negatively charged, and it is not.
C)If atoms contained only negative charges, the particles in the cathode ray would not be attracted toward the anode.
D)He knew that positive charges existed within the atom because the cathode ray was attracted to a negatively charged surface.
3.
The __________ of an isotope is the number of neutrons plus protons.
A)atomic number
B)mass number
C)half-life
D)nucleus number
4.
A(n) __________ is a substance that cannot be broken down into simpler substances.
A)metal
B)compound
C)element
D)mixture
5.
In Rutherford's experiment with alpha particles and gold foil, what was the function of the fluorescent film?
A)It was the electrode and conducted the negative charges through the foil.
B)It was the cathode and generated high-speed electrons.
C)It was used to bend the stream of alpha particles.
D)It flashed when hit by a charged particle and was used to track the motion of the alpha particles.
6.
The changing of one element into another through radioactive decay is called __________ .
A)half-life
B)periodic shift
C)nuclear fusion
D)transmutation
7.
Why don't the protons in the nucleus of an atom repel each other?
A)They are far enough apart that their like charges do not repel each other.
B)They are held together by the strong nuclear force.
C)The negative areas of protons are attracted to the positive areas of other protons and hold the nucleus together.
D)The negatively charged neutrons cancel the net positive charge of the protons in the nucleus.
8.
The __________ of a radioactive isotope is the amount of time it takes for half of a sample of the element to decay.
A)transmutation rate
B)half-life
C)atomic number
D)rate of degradation
9.
Ernest Rutherford experimented with alpha particles and thin gold foil to find out __________ .
A)the speed at which alpha particles travel
B)if Dalton's model of the atom was correct
C)the size of the electron orbit
D)if Thomson's model of the atom was correct
10.
The small, negatively charged particles discovered by J.J. Thomson are called __________ .
A)protons
B)neutrons
C)alpha particles
D)electrons
11.
Which of the following models of the atom reflects the unpredictable motion of the electron?
A)solid ball the same throughout
B)small ball within a large shell containing empty space
C)electron cloud
D)ball of raisin-cookie dough with raisins representing electrons
12.
The __________ of an element is the number of __________ of an atom of that element.
A)atomic mass; protons in the nucleus
B)mass number; protons plus neutrons in the outermost energy level
C)atomic number; protons in the nucleus
D)mass number; neutrons in the nucleus
13.
Rutherford called the positively charged, central part of the atom the __________ .
A)electron
B)proton
C)nucleus
D)neutron
14.
Where did Rutherford propose that the positive charge in an atom was located?
A)moving in predictable orbits around the electrons
B)spread evenly throughout
C)in the center
D)in the outermost energy level
15.
Which of the following would cause a nucleus to be unstable?
A)the release of an alpha particle from americium-241 in a smoke detector
B)protons and neutrons packed tightly in the nucleus
C)equal numbers of protons and neutrons
D)too many neutrons
16.
Which of the following best describes Thomson's model of the atom?
A)solid ball the same throughout
B)electron cloud
C)small ball within a large shell containing empty space
D)ball of raisin-cookie dough with raisins representing electrons
17.
__________ are atoms of the same element that have different numbers of neutrons.
A)Alpha particles
B)Beta particles
C)Compounds
D)Isotopes
18.
What nineteenth century scientist combined the idea of elements with the Greek theory of the atom?
A)J.J. Thomson
B)Isaac Newton
C)John Dalton
D)Ernest Rutherford
19.
How did J.J. Thomson know that the particles in the cathode-ray tube were negatively charged?
A)These particles were attracted to the negatively charged cathode, and he knew that like charges attract each other.
B)The particles were spread evenly throughout the tube.
C)Some of the particles went veering off at large angles to the tube.
D)These particles were attracted to the positively charged anode, and he knew that opposite charges attract each other.
20.
Carbon-14 is useful in determining __________.
A)the age of sedimentary rock layers
B)the age of dead plants and animals
C)how fast a radioactive sample will decay
D)the best method for the disposal of a radioactive sample
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