The type of radioactive particle that can be stopped by a sheet of paper is the _________.

The most penetrating type of radiation is the ______.

One type of radioactive device that indicates the intensity of radiation with a clicking sound that increases in frequency as more radiation is present is the _______________.

A helium nucleus with two protons and two neutrons is called a(n) ______________.

When the strong force is not sufficient to hold unstable nuclei together permanently, __________.

Negatively charged particles emitted from the nucleus at high speed are __________.

The process by which nuclei having low masses are united to form nuclei with larger masses is ________.

The discovery of radioactivity by Henri Becquerel involved a __________.

The stability of an isotope nucleus depends on the ___________.

Radioactive tracers are useful in __________.

Both a fusion and a fission reaction __________.

Neutrons released in a fission reaction can strike other nuclei and cause

For which of the following problems would a scientist most likely use carbon-14?

Thorium-234 has a half life of 24 days. If you started with a 100-g sample of thorium-234, how much would remain after 48 days?

Which of the following elements is most likely to be produced during nuclear fusion in the Sun?

When the __________ is not large enough to hold a nucleus together, the nucleus can become radioactive.

Materials that continue to glow in the dark after they have been exposed to light are said to be:

The first person to recognize the existence of radioactivity was _____________.

The ratio of protons to neutrons in stable isotopes of the lighter elements tends to be approximately _______.

The most difficult type of radiation to block out is _________.

A particle released during the fission of uranium-235 is a(n)

If a neutron begins a nuclear chain reaction, then one product of that reaction must be ___________.

In a reactor, nuclear energy is produced in the _______.

Which of the following was NOT an important scientist in the discovery of radiation?

Which type of radiation is the most penetrating?

Which is the only type of radiation that might penetrate the walls of a house?

Which of the following isotopes is not commonly used for dating objects?

When one large nucleus is split into two smaller nuclei, the process is nuclear _______.

To control a chain reaction, a moderator, such as ________ is used to slow down neutrons.

Two or more nuclei combine to form one larger nucleus in the process of nuclear ___________.

Which produces more energy- nuclear fission or nuclear fusion?

The greatest source of radiation that humans are exposed to is _________.

Most radioactive waste is generated in ________.

The radioisotope iodine-131 is used to determine the health of the thyroid gland. Iodine-131 is an example of a ___________.

Unstable nuclei can break apart spontaneously, changing the identity of the ___________.

__________ is the splitting of nuclei.

__________ is the combining of nuclei.

Alpha particles have a _______ charge.

Beta particles have a _________ charge.

Gamma rays have a ________ charge.