Deck 32: The Atom and the Quantum

Question 1

Alpha particles are normally repelled by atomic nuclei because

A)their closeness with atomic nuclei violates quantum rules.
B)of oppositely-directed forces.
C)they both have the same sign of electric charge.
D)all of the above
E)none of the above

Answer 1

they both have the same sign of electric charge.

Question 2

A beam of electrons can be deflected by a

A)magnetic field.
B)electric field.
C)both of these
D)neither of these

Answer 2

both of these

Question 3

The beam in a cathode-ray tube is composed of

A)photons.
B)electrons.
C)both of these
D)neither of these

Answer 3

electrons.

Question 4

When Rutherford directed a stream of alpha particles at a gold foil, most particles

A)bounced back.
B)continued through.
C)stopped.
D)spiraled.

Question 5

Millikan was able to stop falling oil droplets in their paths by

A)opposing electric and gravitational forces.
B)magnetic repulsion.
C)both of these
D)neither of these

Question 6

Spectral lines for an element are often in the

A)infrared region.
B)ultraviolet region.
C)both of these
D)neither of these

Question 7

When Rutherford directed a stream of alpha particles at a gold foil, some particles

A)bounced back.
B)continued through the foil.
C)deflected at a variety of angles.
D)all of the above
E)none of the above

Question 8

What did Millikan measure in his oil-drop experiment?

A)the electric charge of an electron
B)the mass of an electron
C)the mass of oil drops
D)none of the above

Question 9

Some alpha particles fired at a gold foil bounced backward as a result of

A)reflection from the surfaces of gold atoms.
B)electrostatic repulsion by gold nuclei.
C)electrostatic repulsion by electrons within gold atoms.
D)all of the above
E)none of the above

Question 10

When an electron drops from a higher energy level to a lower one, energy is emitted. In comparison, how much energy is required to reverse the process, going from the lower level to the higher level?

A)less energy
B)the same energy
C)more energy

Question 11

Credit for research in our knowledge of the electron includes

A)William Crookes.
B)J.J. Thomson.
C)Robert Millikan.
D)all of the above
E)none of the above

Question 12

Some alpha particles pass through gold foil with very little deflection mainly because the

A)electric field is zero inside the foil.
B)atoms of gold are mostly empty space.
C)net charge of the gold atoms is zero.
D)all of the above
E)none of the above

Question 13

Credit for research in our knowledge of atomic spectra includes

A)Johann Jacob Balmer.
B)Johannes Rydberg.
C)Walter Ritz.
D)all of the above
E)none of the above

Question 14

Both electrons and protons have equal-magnitude

A)mass.
B)charge.
C)energy.
D)all of the above
E)none of the above

Question 15

By scattering alpha particles from gold, Rutherford showed the atomic nucleus to be very

A)small relative to the atom.
B)massive relative to the mass of an electron.
C)both of these
D)neither of these

Question 16

A beam of electrons is employed in

A)a gold-foil experiment.
B)a cathode-ray tube.
C)a LED television screen.
D)an oil-drop experiment.

Question 17

The first to be credited for assigning the terms positive and negative to electricity was

A)William Crookes.
B)J.J. Thomson.
C)Robert Millikan.
D)Benjamin Franklin.
E)none of the above

Question 18

When Millikan observed oil drops hovering at rest in his chamber, he knew that

A)an upward electric force balanced the weight of each drop.
B)each drop was in mechanical equilibrium.
C)the net force on each drop was zero.
D)all of the above
E)none of the above

Question 19

The spectral lines of atomic spectra are

A)images of the slit in a spectroscope.
B)orderly, and even predictable.
C)as an identity of atoms as fingerprints are of people.
D)all of the above
E)none of the above

Question 20

An excited hydrogen atom is capable of emitting radiation of

A)a single frequency.
B)three frequencies.
C)many more than three frequencies.

Question 21

Two spectral lines in a spectrum have frequencies of 2.0 x 10¹⁴ Hz and 4.6 x 10¹⁴ Hz. A higher-frequency line in the same spectrum likely has a frequency of

A)2.6 x 10¹⁴ Hz.
B)6.6 x 10¹⁴ Hz.
C)13.2 x 10¹⁴ Hz.
D)none of the above

Question 22

According to de Broglie, constructive interference occurs when an orbiting wave

A)reinforces itself
B)doesn't reinforce itself.
C)neither of these

Question 23

The rule stating that the sum of two emitted frequencies in an atomic spectrum equals a third frequency is attributed to the physicist

A)Niels Bohr.
B)Max Planck.
C)W. Ritz.
D)Einstein

Question 24

An excited atom decays to its ground state and emits a photon of green light. If instead the decay is to an intermediate state, then the light emitted could be

A)red.
B)violet.
C)blue.
D)any of the above
E)none of the above

Question 25

The finding that electrons in an atom occupy a volume much greater than the volume of the nucleus is best explained by

A)electromagnetic forces.
B)angular momentum conservation.
C)relative sizes of electrons and nuclei.
D)the wave nature of the electron.
E)none of the above

Question 26

According to the Bohr model, an electron in an excited state of hydrogen can emit

A)at most a single photon until the atom re-excites.
B)several photons in a series of transitions to a lower state.
C)a continuous stream of light.
D)none of the above

Question 27

Discrete radii and energy states of atoms were first explained by electrons circling the atom in an integral number of

A)wave frequencies.
B)de Broglie wavelengths.
C)diffraction patterns.
D)high-speed particles.
E)none of the above

Question 28

The rule stating that the sum of two emitted frequencies in an atomic spectrum equals a third frequency is consistent with

A)momentum conservation.
B)energy conservation.
C)Planck's constant.
D)none of the above

Question 29

A problem with the Bohr model of the atom is that electrons circling the nucleus

A)accelerate and should continuously emit radiation.
B)lose energy and should spiral into the nucleus.
C)both of these
D)neither of these

Question 30

Physicists today consider the Bohr model of the atom to be

A)an accurate picture of a hydrogen atom.
B)totally useless - of historical interest only.
C)oversimplified, but nevertheless useful.

Question 31

The discreteness of orbits of electrons in an atom are due to

A)wave interference.
B)momentum conservation.
C)electric charge quanta
D)all the above
E)none of the above

Question 32

Why electrons don't spiral into atomic nuclei is best explained by their

A)particle nature.
B)wave nature.
C)both of these
D)neither of these

Question 33

When an electron de-excites from the third quantum level to the second, and then to the ground state, two photons are emitted. The sum of the emitted frequencies equals the frequency of the single photon that would be emitted if de-excitation were from the third to

A)the second level.
B)the ground state.
C)any other level.
D)none of the above

Question 34

An excited atom decays to its ground state and emits a photon of red light. If instead the decay is to an intermediate state, then the light emitted could be

A)red.
B)violet.
C)blue.
D)any of these
E)none of these

Question 35

Quantization of electron energy states in an atom is better understood in terms of the electron's

A)wave nature.
B)particle nature.
C)neither of these

Question 36

The discreteness of energy levels is best understood by considering the electrons to be

A)like tiny planets orbiting a sun.
B)attached to the nucleus by massless springs.
C)much less massive than the nucleus.
D)all of the above
E)none of the above

Question 37

According to de Broglie, destructive interference occurs when an orbiting wave

A)reinforces itself
B)doesn't reinforce itself.
C)neither of these

Question 38

What was discovered in atomic spectra by physics pioneers Balmer, Rydberg, and Ritz?

A)unexplained randomness
B)mathematical order
C)all atoms are about the same size
D)electrons occupy well-defined shells about the atomic nucleus
E)electrons behave as standing waves

Question 39

The Bohr model of the atom is akin to a

A)miniature solar system.
B)blob of plum pudding, where raisins represent electrons.
C)central heavy ball with lighter balls connected by springs.
D)all of the above

Question 40

The Ritz combination principle states that the sum of the

A)frequencies of two lines in a spectrum often equal the frequency of a third line.
B)energies associated with two lines in a spectrum often equal the energy associated with a third line.
C)energy transitions of quantum jumps is consistent with the conservation of energy.
D)all of the above
E)none of the above

Question 41

The finding that electrons occupy discrete orbits in an atom was first explained by the

A)quantization of electric charge.
B)small mass of the electron.
C)circumference of each orbit being an integral multiple of an electron wavelength.
D)none of the above

Question 42

A stable electron orbit cannot exist if its circumference is

A)a single wavelength.
B)2 wavelengths.
C)2.5 wavelengths.
D)any of the above
E)none of the above

Question 43

The Schrödinger equation is most useful for describing

A)submicroscopic particles.
B)microscopic particles.
C)macroscopic particles.
D)none of the above

Question 44

A hypothetical atom has four distinct energy states. Assuming all transitions are possible, the number of spectral lines this atom can produce is

A)5.
B)6.
C)7.
D)8.
E)more than 8.

Question 45

The correspondence principle applies to

A)theories of submicroscopic phenomena.
B)theories of macroscopic phenomena.
C)all good theories.

Question 46

Compared with the wavelengths of visible light, the wavelengths of matter waves in atoms are relatively

A)long.
B)short.
C)neither, for all are the same.

Question 47

Unlike Bohr, Schrödinger viewed electrons as

A)fixed in position.
B)traveling in circles.
C)tiny bullets.
D)waves.

Question 48

Using the Schrödinger equation, scientists can calculate

A)probabilities.
B)the position of an electron.
C)the velocity of an electron.
D)all of the above

Question 49

According to the correspondence principle, a new theory must

A)overlap and agrees where the old theory works.
B)account for confirmed results from the old theory.
C)predict the same correct results as the old theory.
D)all of the above
E)none of the above

Question 50

A beam of electrons has

A)wave properties.
B)particle properties.
C)both of these
D)neither of these

Question 51

The thing that "waves" in the Schrödinger equation is a

A)particle's position.
B)particle's momentum.
C)wave function.
D)all of the above
E)none of the above

Question 52

A new theory conforms to the correspondence principle when it

A)corresponds to all theories in nature.
B)updates the essence of the old theory.
C)connects two or more theories.
D)accounts for verified results of the old theory.

Question 53

In the electron-wave model of the atom, an electron in the second energy level contains

A)a single wavelength.
B)two wavelengths.
C)any number of wavelengths.
D)none of the above

Question 54

In the electron-wave model of the atom, the orbit of an electron in the ground state contains

A)a single wavelength.
B)multiple wavelengths.
C)even number quanta.

Question 55

The probability cloud for the electron in the hydrogen atom has an average radius

A)quite different from the radius predicted by Bohr.
B)in agreement with the orbital radius of Bohr.
C)as yet not accurately measured.