purple pen revision

purple pen revision

1. the approximate size of a helium atom is 1x10-10

2. a reason why all atoms have a total of zero charge is because number of electron= number of protons

3. atoms of diffrent beryllium isotopes will have diffrent number of nuetrons

4. the sutructure of an atom to change ito an ion will lose or gain electrons

5. alpha has the shortest range in air

6. gamma is very weakly ionising

7. beta will pass through paper but is stopped by thin metal