Question 1

A nuclear reaction's reaction rate is affected by temperature, pressure, and catalysts.

Accepted Answer

Nuclear reactions are governed by the properties of the atomic nuclei and the energy of the reacting particles, not by temperature, pressure, or catalysts, which primarily affect chemical reactions.

Question 2

A beta particle is a proton.

Accepted Answer

A beta particle is actually an electron or a positron emitted from the nucleus during beta decay, not a proton.

Question 3

The difference between the mass of an atom and the sum of the masses of its protons, neutrons, and electrons is called the ________ ________.

Accepted Answer

The answer of The difference between the mass of an...

Question 4

What are magic numbers with reference to nuclear stability?

Accepted Answer

Magic numbers refer to the numbers of nuclear particles in generally more stable nuclei, specifically those that correspond to completely filled shells of either protons or neutrons. These include 2, 8, 20, 28, 50, 82, and 126.

Question 5

Naturally occurring uranium contains approximately 1% U-235 and 99% U-238. Of these, the isotope that undergoes fission in a nuclear reactor is U-238.

Accepted Answer

The isotope that undergoes fission in a nuclear reactor is U-235, not U-238. The isotope that undergoes fission in a nuclear reactor is actually U-235, not U-238. U-238 can undergo neutron capture to eventually become plutonium-239, which can also undergo fission in a reactor.

Question 6

A gamma particle has a charge of -1.

Accepted Answer

Gamma particles are high energy photons and do not have a charge.

Question 7

All isotopes of elements with atomic numbers higher than 83 (Bi) are radioactive.

Accepted Answer

Isotopes with atomic numbers higher than 83 have unstable nuclei and undergo radioactive decay.

Question 8

Nuclear fission is the process in which a heavy nucleus (mass number > 200) divides to form smaller nuclei of intermediate mass and one or more protons.

Accepted Answer

Nuclear fission is the process in which a heavy nucleus splits into two or more smaller nuclei, along with the release of energy, neutrons, and often other particles. The mass number of the original nucleus does not need to be greater than 200, and the products are not limited to intermediate mass nuclei and protons.

Question 9

Electron capture is the capture of an electron-usually a 1s electron-by the ________.

Accepted Answer

The answer of Electron capture is the capture of an...

Question 10

A plot of the number of neutrons versus the number of protons in various isotopes produces a "belt of stability." Isotopes below the belt of stability (i.e., with a smaller neutron-to-proton ratio) decay by beta particle emission.

Accepted Answer

The answer of A plot of the number of neutrons...

Question 11

The ________ has the same mass as the electron, but bears a charge of +1.

Accepted Answer

The answer of The ________ has the same mass as...

Question 12

For stable atoms of elements having low atomic numbers (≤ 20), the neutron-to-proton ratio is close to zero.

Accepted Answer

For stable atoms of elements having low atomic numbers (≤ 20), the neutron-to-proton ratio is generally close to 1:1, not zero.

Question 13

Nuclear fusion is the combination of small nuclei into larger ones.

Accepted Answer

Nuclear fusion involves combining small nuclei, typically hydrogen isotopes, to form larger ones, such as helium. This process releases a large amount of energy and is the process that powers stars.

Question 14

An alpha particle is a helium atom.

Accepted Answer

An alpha particle is equivalent to a helium nucleus, consisting of 2 protons and 2 neutrons, but it lacks the electrons that would make it a complete helium atom.

Question 15

A radioisotope decays, producing an alpha particle and Th-234. The original radioisotope must have been an atom of ________.

Accepted Answer

When a radioisotope decays by emitting an alpha particle (which consists of 2 protons and 2 neutrons), the atomic number decreases by 2 and the mass number decreases by 4. Th-234 (Thorium-234) has an atomic number of 90 and a mass number of 234. Therefore, the original radioisotope must have had an atomic number of 92 (90 + 2) and a mass number of 238 (234 + 4), which corresponds to Uranium (U).

Question 16

Gamma rays are not deflected by an electric field.

Accepted Answer

Gamma rays do not have any charge, so they are not affected by electric fields. Gamma rays are neutral particles and therefore not affected by electric fields.

Question 17

Gamma rays are high energy electrons.

Accepted Answer

Gamma rays are not electrons, but high energy electromagnetic radiation. Gamma rays are not electrons, they are a type of electromagnetic radiation with extremely high energy and short wavelengths.

Question 18

The ________ ________ ________ is a quantitative measure of the nuclear stability of a nucleus, which is the energy required to break up a nucleus into its component protons and neutrons.

Accepted Answer

The answer of The ________ ________ ________ is a quantitative...

Question 19

Alpha decay is not observed for isotopes of elements with atomic numbers less than 83.

Accepted Answer

Alpha decay can occur in isotopes of elements with atomic numbers less than 83, but it is more common and energetically favorable in heavier elements.

Question 20

In a nuclear reaction elements are converted to other elements.

Accepted Answer

In a nuclear reaction, the nucleus of an atom can undergo changes that may result in the formation of a different element or isotope. This process is called nuclear transmutation. Therefore, elements can be converted to other elements through nuclear reactions.

Quiz 20: Nuclear Chemistry