Radiation

The typical size of an atom is 

• 10–5 m

• 10–10 m

• 10–15 m

• 10–20 m

Which of these describes an alpha particle? 

• a hydrogen nucleus

• a hydrogen atom

• a helium nucleus

• a helium atom

The figure shows the structure of an oxygen-14 atom. 

Which subatomic particle is A? 

• nucleus

• electron

• neutron

• proton

The figure shows the structure of an oxygen-14 atom. 

Which subatomic particle is B? 

• nucleus

• electron

• neutron

• proton

The figure shows the structure of an oxygen-14 atom. 

Which subatomic particle is C? 

• nucleus

• electron

• neutron

• proton

The figure shows the structure of an oxygen-14 atom. 

What is 'D' collectively known as? 

• nucleus

• electron

• neutron

• proton

State the overall charge of the oxygen-14 atom.

Answer explanation

Beryllium-9 has an atomic number of 4 and a mass number of 9.      A nucleus of this isotope can be described using this symbol.

The number of neutrons in this nucleus is 

• 4

• 5

• 9

• 13

Which one of these symbols describes the nucleus of a different isotope of beryllium from Be-9?

• 
• 
• 
• 

Some rocks contained uranium when they were formed. 

Radioactive decay in these rocks produces radon gas. 

Explain why people living near these rocks have an increased health risk from background radiation. 

Answer explanation