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 a(n) ____.

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, ____.

instrument that detects radiation by means of a superheated liquid is a ____.

Negatively charged particles emitted from a nucleus at a high speed are ____.

The discovery of radioactivity by Henri Bequerel involved a ____.

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

The three types of nuclear radiation in increasing order of penetrating power are ____.

The stability of an isotope nucleus depends on the __.

Radioactive tracers are useful in ____.

Both a fusion reaction and a fission reaction ____.

causes chain reactions.

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 a nuclear fusion reaction in the Sun?

uranium-235.

When an electroscope is given a(n) ____, its leaves repel each other and spread apart.

If a source of radiation is placed near ____ cells, atoms in the cells can be ionized and can die or stop growing.

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