A nucleus of uranium 238 decays by alpha emission to form a daughter nucleus, thorium 234. This thorium in turn transforms into protactinium 234, and then undergoes beta-negative decay to produce uranium 234.

Natural uranium consists of three isotopes: uranium-238, uranium-235, and uranium-234. Uranium isotopes are radioactive. The nuclei of radioactive elements are unstable, meaning they are transformed into other elements, typically by emitting particles (and sometimes by absorbing particles).

Thorium-232 (232Th) is present in significant amounts in the Earth’s crust and is an alpha-emitting radionuclide, which decays to radium-228 (228Ra), which is a beta emitter with a half-life of about six years; it emits no significant gamma radiation.

When thorium-234 decays, it releases negatively charged radiation called beta particles. A beta particle is an electron emitted by an unstable nucleus. The symbol for a beta particle is 0e.

Answer: C. The atomic number increase caused by two beta decays is the same as the decrease caused by one alpha decay.

Decay of uranium-235 into thorium-231 and an alpha particle. Larger, more massive nuclei like uranium-235 become more stable by emitting an alpha particle, which is a helium nucleus composed of two protons and two neutrons. This process is known as alpha decay.

1 : of, caused by, or exhibiting radioactivity radioactive isotopes Radon is an odorless, colorless gas that arises naturally from the ground because of the decay of radioactive elements commonly found in rocks and many types of soil.

Bananas are slightly radioactive because they are rich in potassium, and one of its natural isotopes (variants) is potassium-40, which is radioactive. A lorry full of bananas is radioactive enough to trigger a false alarm on a radiation detector looking for smuggled nuclear weapons.

Early and late effects of radiation therapy The most common early side effects are fatigue (feeling tired) and skin changes. Other early side effects usually are related to the area being treated, such as hair loss and mouth problems when radiation treatment is given to this area.

Radiation therapy can also cause hair loss on the part of the body that is being treated. Hair loss is called alopecia. Talk with your health care team to learn if the cancer treatment you will be receiving causes hair loss.

Side effects most often start by the second or third week of treatment. They can last up to several weeks after your final radiation treatment. Many people who get radiation have some fatigue and skin reactions.

Possible symptoms include:

• Nausea and vomiting.
• Diarrhea.
• Headache.
• Fever.
• Dizziness and disorientation.
• Weakness and fatigue.
• Hair loss.
• Bloody vomit and stools from internal bleeding.