1. Beta and Positron Radiation

2. Model of the atom - Recap

3. Protons and neutrons are known as NUCLEONS
Properties of sub-atomic particles
Relative Charge
Relative Mass
Protons and neutrons are known as NUCLEONS

4. Representing Atoms Number of protons and neutrons (or nucleons)
Number of protons only

5. Nuclear Radiation
The nucleus of some unstable atoms (radioisotopes) emit nuclear radiation.
Alpha, beta and gamma are types of nuclear radiation that can be emitted.
gamma
beta
alpha

6. Beta Decay
There are two types of beta particles:- beta minus (electron) and beta plus (positron) -1 - +1 +
Positron
Electron

7. Beta radiation properties
The ß- radiation consists of a stream of high-energy electrons. They are ionising and can penetrate paper and thin sheets of aluminium but are stopped by thin sheets of other metals.

8. The positron is an antiparticle of the electron, it has the same mass but opposite charge
Relative Charge
Relative Mass

9. Beta minus (-) decay

10. (-) + -1 N 14 7 C 6 -

11. Cs Ba -  + Beta minus decay e.g. 2
Caesium 137 (137Cs) undergoes beta negative (β-) decay: + Cs 55
137 Ba 56 
electron -1 -

12. Beta plus (+) decay (higher)
Sodium 22 (22Na) undergoes beta positive (β+) decay: +1 + + Na 11 22 Ne 10 
positron
In beta positive (β+) decay a proton becomes a neutron.

13. Summary Questions