Nuclear Chemistry

What is radioactivity?

The spontaneous decay of an unstable nucleus.

What does 'spontaneous' mean in the context of radioactivity?

It means the decay occurs naturally without external influence, though it can happen slowly.

What is the neutron to proton ratio for small elements (atomic numbers 1-20)?

They typically have a neutron to proton ratio close to 1:1.

What happens to isotopes during nuclear decay?

They undergo decay to achieve a stable neutron to proton ratio.

What is the half-life of a radioactive substance?

The amount of time required for half of a radioactive substance to decay.

How does the stability of a nucleus relate to its half-life?

The more unstable the nucleus, the shorter its half-life.

What is the nuclear mass defect?

The mass of an atom is always less than the sum of its individual particles due to mass converted into energy.

What is the equation relating mass and energy in nuclear reactions?

E = mc², where E is energy, m is mass, and c is the speed of light.

What is alpha decay?

A type of decay that emits 2 protons and 2 neutrons, equivalent to a helium nucleus.

What is beta decay?

Occurs when a neutron is converted into a proton, emitting an electron from the nucleus.

What is gamma radiation?

High-energy radiation emitted from the nucleus, which does not change the composition of the nucleus.

What is positron emission?

The emission of a positively charged electron when a proton is converted into a neutron.

What is electron capture?

A low-energy electron is captured by the nucleus, converting a proton into a neutron.

What is spontaneous fission?

The splitting of an atom into two or more smaller atoms, used in nuclear bombs and power plants.

What are fuel rods in nuclear power plants?

12-18 foot aluminum tubes filled with pellets of enriched uranium.

What is the purpose of control rods in a nuclear reactor?

To absorb neutrons and control the rate of the nuclear reaction.

What is the difference between a Boiling Water Reactor (BWR) and a Pressurized Water Reactor (PWR)?

BWR allows water to boil inside the reactor, while PWR keeps water under pressure and superheats it without boiling.

What is critical mass in the context of nuclear bombs?

The minimum amount of fissionable material required to sustain a chain reaction.

What are the two types of atomic bombs?

Gun-triggered bombs, which use U-235, and implosion-triggered bombs, which use Pu-239.

What is the significance of Radon in radioactive decay?

Radon is the only radioactive element that can diffuse through cracks in the Earth's crust and is a second leading cause of lung cancer.

What is enriched uranium?

Uranium that has a higher percentage of U-235 than found in natural uranium.

What is yellowcake?

A purified form of uranium oxide that is golden yellow in color, used in the enrichment process.

What is the role of moderators in a nuclear reactor?

To slow down neutrons so they can be absorbed by the nucleus.

What was the Chernobyl disaster?

The worst nuclear accident in history, occurring in 1986, resulting in widespread radioactive contamination.

What is the difference between neutron-rich and neutron-deficient isotopes?

Neutron-rich isotopes are beta emitters, while neutron-deficient isotopes are positron emitters.

What happens during a decay series?

Nuclei undergo multiple decay steps before stabilizing, such as Uranium decaying into Lead-206.