Deck 32: The Atom and the Quantum

Question 1

Physics pioneers Balmer,Rydberg,and Ritz discovered in atomic spectra

A)a randomness that opened the door to the nature of probabilities in atomic reality.
B)mathematical order.
C)that all atoms are essentially the same size.
D)that electrons occupy well-defined shells about the atomic nucleus.
E)that electrons behave as standing waves.

Answer 1

mathematical order.

Question 2

Compared to the average diameter of a hydrogen atom,the average diameter of a helium atom is

A)larger.
B)smaller.
C)about the same.

Answer 2

smaller.

Question 3

Orbital electrons do not spiral into the nucleus because of

A)electromagnetic forces.
B)angular momentum conservation.
C)the large nuclear size compared to the electron's size.
D)the wave nature of the electron.
E)none of these

Answer 3

the wave nature of the electron.

Question 4

A key feature of the theory of chaos is

A)unpredictability.
B)very small initial differences can lead to very large eventual differences.
C)the randomness of molecular motion makes prediction difficult.
D)even orderly systems are seen to be disorderly when carefully studied.

Question 5

An excited hydrogen atom is capable of emitting radiation of

A)a single frequency.
B)3 frequencies.
C)many more than 3 frequencies.

Question 6

The Schrödinger equation is restricted to

A)submicroscopic particles.
B)submicroscopic and microscopic particles.
C)macroscopic particles.
D)none of these

Question 7

When Rutherford had a stream of alpha particles hit a gold foil,most of the particles

A)bounced back.
B)went almost straight through.
C)stopped.
D)spiraled.

Question 8

We now 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)defective and oversimplified,but still useful.

Question 9

In the Bohr model of hydrogen,discrete radii and energy states result when an electron circles the atom in an integral number of

A)wave frequencies.
B)de Broglie wavelengths.
C)diffraction patterns.
D)none of these

Question 10

A beam of electrons has

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

Question 11

The Bohr model of the atom is akin to a

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

Question 12

The discreteness of energy levels is better 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 these
E)none of these

Question 13

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 14

Some alpha particles fired through a gold foil bounce backward by

A)making direct hits with gold atoms.
B)electrostatic repulsion when close to gold nuclei.
C)electrostatic repulsion with the electron clouds of gold atoms.
D)all of these
E)none of these

Question 15

According to Niels Bohr,an electron in an excited state could give off

A)at most a single photon until the atom was excited again.
B)several photons in a series of transitions to the ground state.
C)a continuous cascade of photons for a high-level transition.
D)none of these

Question 16

Alpha particles are repelled by atomic nuclei because

A)of the repelling interaction between an alpha particle and the atomic nucleus.
B)closeness of each to each other is not permitted.
C)the force between the alpha particle and the atomic nucleus is opposite to an attractive force.
D)they both have the same sign of electric charge.
E)none of these

Question 17

Heavy atoms are not appreciably larger in size than light atoms because the nuclei of heavy atoms have more

A)mass.
B)electric charge.
C)nucleons.
D)all of these
E)none of these

Question 18

A uranium atom is 238 times as massive as a hydrogen atom.The diameter of a uranium atom is the diameter of a hydrogen atom times about

A)3)
B)10.
C)30.
D)100.
E)238.

Question 19

Most alpha particles fired at a gold foil pass through undeflected because the

A)electric field is zero inside the gold.
B)gold atoms,unlike most other metal atoms,are relatively far apart.
C)atoms of gold,like any others,are mostly empty space.
D)net charge of the gold atoms is zero.
E)none of these

Question 20

According to the correspondence principle,a new theory is valid if it

A)overlaps and agrees where the old theory works.
B)accounts for confirmed results from the old theory.
C)predicts the same correct results as the old theory.
D)all of these
E)none of these

Question 21

What do electrons have that protons always have in equal magnitude?

A)mass
B)charge
C)energy
D)all of these
E)none of these

Question 22

If atoms were smaller,Planck's constant would be

A)larger.
B)smaller.
C)no different in physical size.

Question 23

A hypothetical atom has four distinct energy states.Assuming all transitions are possible,how many spectral lines can this atom produce?

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

Question 24

The electrical force between an inner electron and the nucleus of an atom is larger for atoms of

A)low atomic number.
B)high atomic number.
C)the same for both

Question 25

Compared to the wavelengths of visible light,the wavelengths of matter waves are relatively

A)large.
B)small.

Question 26

The main reason electrons occupy discrete orbits in an atom is because

A)energy levels are quantized.
B)electric forces act over quantized distances.
C)electrons are basically discrete particles.
D)the circumference of each orbit is an integral multiple of electron wavelengths.
E)none of these

Question 27

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

A)quite different from the radius predicted by Bohr.
B)that agrees with the orbital radius of Bohr.

Question 28

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)ties two or more theories together.
D)accounts for verified results of the old theory.
E)none of these

Question 29

The correspondence principle applies to

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

Question 30

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

A)energy conservation.
B)the physicist W.Ritz.
C)both of these
D)neither of these

Question 31

Compared to the diameter of a zirconium atom (A = 40),the diameter of a mercury atom (A = 80)is approximately

A)four times as large.
B)twice as large.
C)the same size.
D)one-half as large.
E)one-quarter as large.

Question 32

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

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