Question 1

The normal U.S. average annual radiation dose per person is about how many REM?

Accepted Answer

0.20

Question 2

Discuss what observations convinced Rutherford that the nucleus was very small and dense.

Accepted Answer

Alpha scattering from heavy nuclei produced much more backscattering than would be expected from a diffuse nuclear cloud. Only a dense compact nucleus of positive charge could account for the scattering at large angles.

Question 3

Why do the high-proton-number elements tend to get more unstable?

Accepted Answer

The repulsive electrostatic force between protons increases progressively as atomic number increases, but the nuclear attractive force is short range and the average distance between particles increases as the nucleus size increases.

Question 4

Name five different types of radiation detectors.

Accepted Answer

The answer of Name five different types of radiation detectors....

Question 5

J. J. Thomson
A) observed back-scattering from nuclei.
B) proposed the tiny central nucleus idea.
C) proposed the plum-pudding model.
D) discovered radium and polonium.
E) invented the particle detector tube.

Accepted Answer

J. J. Thomson is best known for proposing the plum-pudding model of the atom, where electrons were thought to be embedded within a positively charged "soup."

Question 6

Ernest Rutherford
A) observed back-scattering from nuclei.
B) proposed the tiny central nucleus idea.
C) proposed the plum-pudding model.
D) invented the particle detector tube.
E) discovered radium and polonium.

Accepted Answer

The answer of Ernest Rutherford
A) observed back-scattering from nuclei.
B) proposed...

Question 7

Compared to the electrostatic force, the nuclear force between adjacent protons in a nucleus is
A) about the same size.
B) only slightly weaker.
C) only slightly larger.
D) much weaker.
E) much stronger.

Accepted Answer

The nuclear force, also known as the strong nuclear force or strong force, is much stronger than the electrostatic force at the short distances within an atomic nucleus. This is why it can overcome the electrostatic repulsion between protons to hold the nucleus together.

Question 8

The number of protons in a neutral atom is
A) equal to the number of neutrons.
B) equal to the number of electrons.
C) called the mass number.
D) the same for all elements.
E) zero.

Accepted Answer

The number of protons in a neutral atom is equal to the number of electrons to maintain electrical neutrality.

Question 9

An atom's mass number is determined by the number of
A) protons in its nucleus.
B) nucleons in its nucleus.
C) electron masses in its nucleus.
D) neutrons in its nucleus.
E) alpha particles in its nucleus.

Accepted Answer

The mass number of an atom is determined by the total number of nucleons in its nucleus, which includes both protons and neutrons.

Question 10

Isotopes of an element have nuclei with
A) a different number of protons, and the same numbers of neutrons.
B) the same number of protons, but different numbers of electrons.
C) a different number of protons, and a different number of neutrons.
D) the same number of protons, but different numbers of neutrons.
E) the same number of protons, and the same number of neutrons.

Accepted Answer

Isotopes of an element have the same number of protons (which defines the element) but differ in the number of neutrons in their nuclei. This results in isotopes having different atomic masses.

Question 11

All isotopes are unstable which have proton number greater than
A) 83.
B) 12.
C) 73.
D) 78.
E) 26.

Accepted Answer

All isotopes with a proton number (atomic number) greater than 83 (bismuth) are unstable, meaning they are radioactive.

Question 12

When an alpha particle is emitted from an unstable nucleus, the atomic mass number of the nucleus
A) increases by 2.
B) decreases by 4.
C) stays unchanged.
D) decreases by 2.
E) increases by 4.

Accepted Answer

When an alpha particle (which consists of 2 protons and 2 neutrons) is emitted from a nucleus, the atomic mass number decreases by 4 because the nucleus loses 4 nucleons (2 protons and 2 neutrons).

Question 13

When a neutron is emitted from an unstable nucleus, the atomic mass number of the nucleus
A) does not change.
B) decreases by 2.
C) increases by 2.
D) increases by 1.
E) decreases by 1.

Accepted Answer

When a neutron is emitted from an unstable nucleus, the atomic mass number decreases by 1 because the nucleus loses one neutron, and the atomic mass number is the total number of protons and neutrons in the nucleus.

Question 14

When a $\beta$+ particle is emitted from an unstable nucleus, the atomic number of the nucleus
A) increases by 2.
B) does not change.
C) decreases by 2.
D) increases by 1.
E) decreases by 1.

Accepted Answer

The answer of When a $\beta$+ particle is emitted from...

Question 15

Marie & Pierre Curie
A) discovered radioactivity.
B) proposed the plum-pudding model.
C) observed back-scattering from nuclei.
D) discovered radium and polonium.
E) proposed the tiny central nucleus idea.

Accepted Answer

Marie and Pierre Curie are known for their discovery of the elements radium and polonium.

Question 16

Henri Becquerel
A) proposed the tiny central nucleus idea.
B) discovered radioactivity.
C) invented the particle detector tube.
D) discovered radium and polonium.
E) observed back-scattering from nuclei.

Accepted Answer

Henri Becquerel discovered radioactivity in 1896 when he found that uranium salts emitted rays that could penetrate through solid matter, fog photographic plates, and cause air to conduct electricity.

Question 17

Which isotopes are radioactive?
A) none
B) some
C) odd numbered
D) even numbered
E) all

Accepted Answer

Some isotopes are radioactive, while others are stable. The radioactivity of an isotope depends on the balance of protons and neutrons in its nucleus, not solely on whether it has an odd or even number of nucleons or its overall abundance.

Question 18

When an alpha particle is emitted from an unstable nucleus, the atomic number of the nucleus
A) increases by 2.
B) decreases by 4.
C) decreases by 2.
D) increases by 4.
E) increases by 6.

Accepted Answer

The answer of When an alpha particle is emitted from...

Question 19

When a nucleus undergoes beta-minus decay, it changes into
A) a higher atomic number.
B) a higher neutron number.
C) a higher mass number.
D) another isotope of itself.
E) a lower proton number.

Accepted Answer

During beta-minus decay, a neutron in an unstable nucleus is transformed into a proton, an electron (beta particle), and an antineutrino. This increases the atomic number by 1, changing the element to the next higher atomic number but does not change the mass number since a neutron is converted into a proton.

Question 20

In radioactive dating, carbon-14 is often used. This nucleus emits a single beta particle when it decays. When this happens, the resulting nucleus is
A) carbon-15.
B) carbon-13.
C) nitrogen-14.
D) still carbon-14.
E) boron-14.

Accepted Answer

When carbon-14 decays by emitting a beta particle (an electron), it loses a neutron but gains a proton, thus becoming nitrogen-14. This is because the atomic number (which defines the element) increases by one, changing from carbon to nitrogen, while the mass number remains the same.

Quiz 29: The Nucleus

The normal U.S. average annual radiation dose per person is about how many REM?

Discuss what observations convinced Rutherford that the nucleus was very small and dense.

Why do the high-proton-number elements tend to get more unstable?

Name five different types of radiation detectors.

J. J. Thomson

Ernest Rutherford

Compared to the electrostatic force, the nuclear force between adjacent protons in a nucleus is

The number of protons in a neutral atom is

An atom's mass number is determined by the number of

Isotopes of an element have nuclei with

All isotopes are unstable which have proton number greater than

When an alpha particle is emitted from an unstable nucleus, the atomic mass number of the nucleus

When a neutron is emitted from an unstable nucleus, the atomic mass number of the nucleus

When a $\beta$ + particle is emitted from an unstable nucleus, the atomic number of the nucleus

Marie & Pierre Curie

Henri Becquerel

Which isotopes are radioactive?

When an alpha particle is emitted from an unstable nucleus, the atomic number of the nucleus

When a nucleus undergoes beta-minus decay, it changes into

In radioactive dating, carbon-14 is often used. This nucleus emits a single beta particle when it decays. When this happens, the resulting nucleus is

Quiz 29: The Nucleus

The normal U.S. average annual radiation dose per person is about how many REM?

Discuss what observations convinced Rutherford that the nucleus was very small and dense.

Why do the high-proton-number elements tend to get more unstable?

Name five different types of radiation detectors.

J. J. Thomson

Ernest Rutherford

Compared to the electrostatic force, the nuclear force between adjacent protons in a nucleus is

The number of protons in a neutral atom is

An atom's mass number is determined by the number of

Isotopes of an element have nuclei with

All isotopes are unstable which have proton number greater than

When an alpha particle is emitted from an unstable nucleus, the atomic mass number of the nucleus

When a neutron is emitted from an unstable nucleus, the atomic mass number of the nucleus

When a β\betaβ + particle is emitted from an unstable nucleus, the atomic number of the nucleus

Marie & Pierre Curie

Henri Becquerel

Which isotopes are radioactive?

When an alpha particle is emitted from an unstable nucleus, the atomic number of the nucleus

When a nucleus undergoes beta-minus decay, it changes into

In radioactive dating, carbon-14 is often used. This nucleus emits a single beta particle when it decays. When this happens, the resulting nucleus is

When a $\beta$ + particle is emitted from an unstable nucleus, the atomic number of the nucleus