Radioactivity

Name the instrument used to detect radioactivity.

• voltmeter
• ohmeter
• seismograph
• geiger counter

What makes something radioactive?

• elements with an atomic number above 81
• an unstable nucleus
• contaminated sewage
• It decays over time

An isotope of an element has the same number of _________, but a different number of _________.

• Protons, electrons
• Protons, neutrons
• Electrons, neutrons

What is Half-life?

• The amount of time it takes for some of the nuclei in a sample of the isotope to decay
• The amount of time it takes for half the electrons in a sample of the isotope to decay
• The amount of time it takes for half the nuclei in a sample of the isotope to decay
• the amount of time it takes to double the nuclei in a sample of the isotope to decay

Radioactive tracers are useful in ____.

• calculating the ages of fossils 
• fueling nuclear reactions 
• determining medical problems 
• treating brain tumors 

An alpha particle is made up of

• 2 protons and 4 neutrons

• 1 proton and 1 neutron

• 2 protons and 2 neutrons

• 4 protons and 2 neutrons

Which type of nuclear radiation can be stopped by a sheet of paper?

• Alpha

• Beta

• Gamma

What type of radioactive decay is shown here?

• Alpha decay
• Beta decay
• Gamma decay

When a substance undergoes beta decay

• The atomic number increases by 1

• The atomic number decreases by 2

• The atomic number does not change

Which type(s) of radiation is the most ionising?

• alpha

• beta

• gamma

• alpha and beta

• beta and gamma