Radioactivity

Question 1

What occurs during alpha decay?

Answer 1

Nucleus expels 2 protons and 2 neutrons, also called an alpha particle.

Question 2

What happens during beta minus decay?

Answer 2

A neutron is converted into a proton, causing the creation of an electron and antineutrino.

• Mass number unchanged
• Proton number increases by 1

Question 3

What happens during beta-plus decay?

Answer 3

A proton is converted into a neutron, causing the creation of a neutrino and positron.

• Mass number stays the same
• Proton number decreases by 1

Question 4

What happens during gamma decay?

Answer 4

A nucleus emits energy in the form electromagnetic radiation of an extremely high frequency.
This is done to stabilise an unstable nucleus.

Question 5

What is the formula for power of a radioactive source?

Answer 5

Power (P) = Activity (A) + Energy of each emitted particle (E)

Question 6

What is the decay constant?

Answer 6

The decay constant (λ) is the probability of an individual nucleus decaying per second.

Question 7

What is binding energy?

Answer 7

Binding energy is the work that must be done to separate a nucleus into its constituent neutrons and protons

Binding energy = Mass defect - speed of light squared

Question 8

What is mass defect?

Answer 8

Mass defect (Δm) is the difference between the mass of a nucleus and its separated, constituent ions.

Mass defect = (mass of nucleus) - (mass of nucleons)