What is an atom?

• The smallest part of an element

• A substance made of two or more elements, chemically joined

• A substance made of two or more elements, not chemically joined

• The largest part of an element

What is the radius of an atom?

• 1 x 10^-10 m

• 1 x 10¹⁰ m

• 1/1000 m

What is an isotope?

• An atom of an element with a different number of neutrons

• An atom of an element with a different number of protons

• An atom of an element with a different number of electrons

What is an ion?

• An atom of an element with a different number of neutrons

• An atom of an element with a different number of protons

• An atom of an element with a different number of electrons

What is radioactive decay?

• An unstable nucleus breaks down to become more stable, giving off radiation

• An unstable atom breaks down to become more stable, giving off radiation

• An unstable element breaks down to become more stable, giving off radiation

• An unstable compound breaks down to become more stable, giving off radiation

What is activity?

• The rate that nuclei decay

• The rate that ions decay

• The rate that protons decay

• The rate that electrons decay

What is the unit of activity?

• Becquerels (Bq)

• Coulombs (C)

• Hertz (Hz)

• Pascals (Pa)

What is count rate?

• Number of decays per second by a Geiger-Muller tube

• Number of ions per second by a Geiger-Muller tube

• Number of atoms per second by a Geiger-Muller tube

• Number of neutrons per second by a Geiger-Muller tube

What is half life?

• The time taken for half of the nuclei in a sample to decay

• The time taken for half of the atoms in a sample to decay

• The time taken for half of the ions in a sample to decay

• The time taken for half of the neutrons in a sample to decay

What is contamination?

• Coming into contact with radioactive materials

• Being exposed to radioactive materials