Radioactivity

Question 1

What do radioactive substances do naturally?

Answer 1

Decay, giving out alpha, beta and gamma radiation.

Question 2

What does nuclear radiation do to atoms?

Answer 2

Cause ionisation by making them lose or gain electrons.

Question 3

Why is the average count rate of radioisotopes always about the same value?

Answer 3

There are so many atoms.

Question 4

Why do radioisotopes have unstable nuclei?

Answer 4

Their nuclear particles aren’t held together strongly enough.

Question 5

What is half-life?

Answer 5

The amount of time it takes for half of a radioactive substance to decay.

Question 6

What is a nucleon?

Answer 6

A particle found in the nucleus, protons and neutrons.

Question 7

What happens to nucleus when alpha and beta particles are emitted?

Answer 7

The remaining nucleus is a different element because the atomic number changes?

Question 8

What are the properties of alpha radiation?

Answer 8

• Helium nucleus (2 protons, 2 neutrons)
• Has a large mass (Ar of 4)
• Positively charged (no electrons)
• Has helium gas around it

Question 9

What are the properties of beta radiation?

Answer 9

• An electron
• Negatively charged
• Very little mass
• Travels very fast

Question 10

What happens to the nucleus when an alpha particle is given out?

Answer 10

• Mass number decreases by 4 (4 nucleons have been lost)

- Atomic number decreases by 2 (2 protons have been lost)

Question 11

What happens to the nucleus when a beta particle is given out?

Answer 11

• Mass number is unchanged (doesn’t have any mass)

- Neutron turns into a proton to balance the charge out (atomic number increases by 1)