AnswersMISD CR Chemistry AUnit Test

Unit Test — Unit test Answers

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Who was the first to propose the existence of atoms?

A
John Dalton
B
Democritus
C
Joseph Proust
D
Ernest Rutherford
2
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Which scientist is known for developing the planetary model of the atom?

A
Niels Bohr
B
Albert Einstein
C
Johannes Rydberg
D
Robert Millikan
3

Iron, an element with the chemical symbol Fe, is an important element. It is used to make steel and is part of the substance that transports oxygen throughout the human body.Which statement about Fe is supported by the modern atomic theory but not John Dalton’s theory?

A
The element iron is composed of small particles called atoms.
B
The electrons of iron have probable locations in a region of space around the nucleus.
C
Iron atoms combine with other atoms in whole number ratios to form compounds.
D
Chemical reactions that involve iron do not create new atoms of iron.
4

Which describes Ernest Rutherford’s experiment?

A
Positive particles are fired at gold foil. Most bounce back, but some pass through.
B
Negative particles are fired at gold foil. Most bounce back, but some pass through.
C
Positive particles are fired at gold foil. Most pass through, but some bounce back.
D
Negative particles are fired at gold foil. Most pass through, but some bounce back.
5

A single atom of an element has 11 protons, 11 electrons, and 12 neutrons. Which element is it?

A
V
B
Na
C
Mg
D
Se
6

Which element has 32 protons in its nucleus?

A
phosphorus
B
cobalt
C
germanium
D
sulfur
7

How did Niels Bohr describe electrons in his atomic model?

A
Their energies can have any values.
B
Their exact positions cannot be known.
C
They have high probability to be found in certain regions.
D
They orbit the central nucleus in discrete paths.
8

Which of Dalton's ideas about the atom did J.J. Thomson's experiment disprove?

A
It disproved that atoms are divisible.
B
It disproved that atoms are indivisible.
C
It disproved that atoms contain protons.
D
It disproved that atoms contain electrons.
9

The diagram below shows some subatomic particles.Which of these statements best identifies the particle that is labeled with an X?

Question illustration
A
It is either a nucleus or a proton.
B
It is either a proton or a neutron.
C
It is either a neutron or an electron.
D
It is either an electron or a nucleus.
10

What did Ernest Rutherford’s gold foil experiment demonstrate about an atom?

A
Each atom is composed of electrons and positive material.
B
The mass of the atom is evenly spread throughout the atom.
C
Neutrons are located in the center of the atom.
D
Positive charge occupies a very small volume in the atom.
11

Hydrogen has three isotopes 1H, 2H, and 3H. What is the difference between these three isotopes?

A
The number of protons ranges from 1 to 3.
B
The number of electrons ranges from 1 to 3.
C
The number of neutrons ranges from 0 to 2.
D
The number of protons ranges from 0 to 2.
12

Frank and Lisa are analyzing the chart, which shows the speed at which light travels through different media.Frank says that light travels through diamond with the greatest frequency. Lisa says that light travels through air with the greatest frequency.

Question illustration
A
Frank is correct because light travels through diamond at the slowest speed, and speed and frequency have an inverse relationship.
B
Lisa is correct because light travels through air at the fastest speed, and speed and frequency have a direct relationship.
C
Neither person is correct because light does not change frequency when it travels through different media.
D
Both people are correct because light has both an inverse and a direct relationship with frequency, depending on the media.
13

As the frequency of electromagnetic waves increases, what happens to the wavelength?

A
It increases.
B
It decreases.
C
It fluctuates.
D
It remains constant.
14

What do all electromagnetic waves have in common?

A
They can travel at the speed of light.
B
They have the same wavelengths.
C
They travel only through matter.
D
They have nonmoving magnetic fields.
15

An atom of element Be has four protons, four electrons, and five neutrons. Which element below could be an isotope of this atom?

A
sodium-10
B
beryllium-10
C
boron-9
D
carbon-9
16

Which best describes the effect of J. J. Thomson’s discovery?

A
The accepted model of the atom was changed.
B
The accepted model of the atom was supported.
C
Cathode ray tubes were no longer used in experiments due to poor results.
D
Cathode ray tubes became the only instrument of use in the study of atoms.
17

Which is the correct formula for finding the frequency of an electromagnetic wave?

A
f = c –
Option A
B
f =
Option B
C
f = + c
Option C
D
f =
Option D
18

A scientist uses an accelerator and high energy electrons to study the particles inside the protons of a helium atom. What particles is the scientist studying?

A
the He neutrons
B
the He nucleus
C
the He electrons
D
the He quarks
19

The chart shows the speed at which light travels through different media.

Question illustration
A
water
B
air
C
glass
D
diamond
20

Isla made a diagram to compare X-rays and radio waves.What should Isla write in the areas marked A, B, and C?

Question illustration
A
A: Has a longer wavelength B: Can travel only through matterC: Has a higher frequency
B
A: Has a higher frequencyB: Can travel only through matterC: Has a longer wavelength
C
A: Has a higher frequencyB: Travels at the same speedC: Has a longer wavelength
D
A: Has a longer wavelength B: Travels at the same speedC: Has a higher frequency

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