Radioactive Decay (P1)

Question 1

Alpha particle

Answer 1

Two protons and two neutrons
Mass number falls by four
Atomic number drops by two
Up to 10cm range
Stopped by paper
Strongly ionising
Symbol is the same as proportion 
Deflected by a magnetic field, attracted to negative plate as they are positive

Question 2

Beta particle

Answer 2

An electron formed when a neutron becomes a proton
Atomic mass doesn’t change
Atomic number increases by one
Around 1m range
Stopped by 5mm of aluminium
Weakly ionising
Symbol is a B with the long line going below
Deflected the other way to beta particles as they are negatively charged

Question 3

Gamma ray

Answer 3

Releases energy from the nucleus
No change to the element
A few km range
60cm+ lead stops it
Very weakly ionising
Symbol is a y with a curvy left line and the long one straight
Not deflected by a magnetic field as they aren’t charged

Question 4

Half life

Answer 4

The time it takes for the activity (number of atoms in the original isotope) to decrease by a half
Random process for individual atoms
Predictable for a large number