Radioactivity Introduction Review Physical Science

What is radioactivity?

• A term that describes the forces that hold atomic nuclei together

• The movement of electrons around an atomic nucleus

• The application of heat energy to an atomic nucleus

• The emission of high-energy particles or waves from atoms

How do atoms with stable nuclei differ from atoms with unstable nuclei? a. b. c. d.

• Stable nuclei can be found everywhere; unstable nuclei do not occur in nature.

• Stable nuclei emit electrons; unstable nuclei emit protons and neutrons.

• Stable nuclei contain equal numbers of protons and neutrons; unstable nuclei do not.

• The number of particles in stable nuclei never changes; the number of particles in unstable nuclei does change.

What would two different isotopes of an atom have in common?

• Atomic weight

• Number of protons

• Number of neutrons

• Atomic mass

What is a half-life?

• The average time it takes for any element to disappear completely

• The time it takes for half of any number of radioactive atoms to decay

• The time it takes for a radioactive atom to lose half its neutrons

• The time it takes for a radioactive atom to lose half its electrons

What does radioactivity mean?

The nucleus of the atom is made of neutrons and electrons.

• Agree

• Disagree

Protons and neutrons are approximately the same size.

• Agree

• Disagree

The majority of an atom's mass is located in the nucleus.

• Agree

• Disagree

An atom with 12 protons and 14 neutrons has a mass number of 26.

• Agree

• Disagree

An atom with 6 protons, 6 neutrons, and 6 electrons has an atomic number of 12.

• Agree

• Disagree