Florida Science Grade 7

Chapter 3: Inside the Atom

Inside the Atom

1
How did J.J. Thomson know that the beam in the cathode-ray tube was not light?
A)It could not be seen without a microscope.
B)Light is not made up of particles.
C)The negatively charged particles in the beam were attracted to the negatively charged cathode.
D)He used a magnet to bend the beam, and light cannot be bent by a magnet.
2
Which of the following models of the atom reflects the unpredictable motion of the electron?
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
3
A(n) __________ is a substance that cannot be broken down into simpler substances.
A)element
B)compound
C)mixture
D)metal
4
Elements created by artificial transmutations are called __________.
A)synthetic elements
B)alpha products
C)isotopes
D)degraded elements
5
How did J.J. Thomson know that the particles in the cathode-ray tube were negatively charged?
A)Some of the particles went veering off at large angles to the tube.
B)The particles were spread evenly throughout the tube.
C)These particles were attracted to the negatively charged cathode, and he knew that like charges attract each other.
D)These particles were attracted to the positively charged anode, and he knew that opposite charges attract each other.
6
The __________ of an element is the number of __________ of an atom of that element.
A)mass number; protons plus neutrons in the outermost energy level
B)atomic number; protons in the nucleus
C)atomic mass; protons in the nucleus
D)mass number; neutrons in the nucleus
7
What nineteenth century scientist combined the idea of elements with the Greek theory of the atom?
A)J.J. Thomson
B)John Dalton
C)Ernest Rutherford
D)Isaac Newton
8
A piece of metal that can conduct electricity is called a(n) __________ .
A)alpha particle
B)electrode
C)foil
D)electron
9
In Rutherford's experiment with alpha particles and gold foil, what was the function of the fluorescent film?
A)It was the cathode and generated high-speed electrons.
B)It flashed when hit by a charged particle and was used to track the motion of the alpha particles.
C)It was used to bend the stream of alpha particles.
D)It was the electrode and conducted the negative charges through the foil.
10
__________ is the release of nuclear particles and energy.
A)Carbon dating
B)Atomic half-life
C)Transmutation
D)Radioactive decay
11
Where did Rutherford propose that the positive charge in an atom was located?
A)spread evenly throughout
B)in the outermost energy level
C)moving in predictable orbits around the electrons
D)in the center
12
The __________ of an isotope is the number of neutrons plus protons.
A)mass number
B)nucleus number
C)atomic number
D)half-life
13
__________ are atoms of the same element that have different numbers of neutrons.
A)Alpha particles
B)Beta particles
C)Isotopes
D)Compounds
14
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)rate of degradation
C)half-life
D)atomic number
15
Ernest Rutherford experimented with alpha particles and thin gold foil to find out __________ .
A)the speed at which alpha particles travel
B)if Thomson's model of the atom was correct
C)the size of the electron orbit
D)if Dalton's model of the atom was correct
16
Why don't the protons in the nucleus of an atom repel each other?
A)The negative areas of protons are attracted to the positive areas of other protons and hold the nucleus together.
B)They are far enough apart that their like charges do not repel each other.
C)They are held together by the strong nuclear force.
D)The negatively charged neutrons cancel the net positive charge of the protons in the nucleus.
17
What particle in an atom is electrically neutral?
A)electron
B)neutron
C)proton
D)alpha
18
The small, negatively charged particles discovered by J.J. Thomson are called __________ .
A)alpha particles
B)neutrons
C)protons
D)electrons
19
The changing of one element into another through radioactive decay is called __________ .
A)nuclear fusion
B)half-life
C)transmutation
D)periodic shift
20
Rutherford called the positively charged, central part of the atom the __________ .
A)proton
B)nucleus
C)electron
D)neutron
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