Radioactivity and Nuclear Decay

The mass number is the number of neutrons and electrons that are part of the nucleus.

• True

• False

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

• alpha particle

• beta particle

• gamma ray

• uranium

The most penetrating type of radiation is the ____.

• alpha particle

• beta particle

• gamma ray

• uranium

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

• alpha particle

• beta particle

• electroscope

• gamma ray

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

• alpha particles

• beta particles

• gamma rays

• X rays

The discovery of radioactivity by Henri Becquerel involved a ____.

• bubble chamber

• chain reaction

• Geiger counter

• photographic plate

The stability of an isotope nucleus depends on the ____.

• atomic mass

• atomic number

• number of neutrons

• neutron-to-proton ratio

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

• reactions

• atoms

• compounds

Alpha particles have a _____ charge.

• -1

• 0

• +1

• +2

Beta particles have a _____ charge.

• -1

• 0

• +1

• +2