1. Nuclear Nat 5 1234 5 67 8910 12 11

2. Why is radiation emitted from atoms? Because there nucleus is unstable. Due to the proton to neutron ratio.

3. A alpha particle consists of… 2 protons and 2 neutrons: it is a a helium atom.

4. Beta radiation is described as … A high speed electron

5. Gamma radiation is described as … A wave

6. Alpha is stopped by… Thin paper and a few cm of air.

7. Beta is stopped by… Thick lead, concrete and Aluminium.

8. Gamma is stopped by… Concrete or lead.

9. 6g of a radioactive isotope of 60 Co has a half-life of 5 yrs. how much of this isotope would be left after 20 yrs? The half life of a radio active isotope is a measure of the time is takes for activity to be reduced by half. Over a period of 20 years, 4 half-lives would be needed. 60 Co 6g 3g1.5g 0.75g 0.375g

10. What is the result of an atom losing an alpha  particle? An alpha particle is a helium nucleus. So is made up from 2 protons and 2 neutrons. It has a atomic number of 2 and a mass number of 4. So the atomic number decreases by 2 and the mass number decreases by 4.

11. What type of reaction is occurring in the process below? Nuclear fission this involves the splitting of a nucleus into two nucleui. 3 92 0 1 U 236 + 56 Ba 142 36 Kr 91 +

12. What is produced (X) when 238 U is combined with a neutron. Adding a neutron means the mass number will increase by 1, but the atomic number will not change. n 0 1 U 238 + e 0 + X X = 93 Pu 239

13. 131 I can be used to study diseased thyroid glands. Its half-life is 8 days. A patient was given 0.0053 mol of this isotope. How many grams would be left after 16 days? The mass of 131 I in 0.0053g = n (number moles) = mass/gfm So mass = n x gfm=0.0053x131= 0.694g 131 I 0.694g0.347g 0.174g 8 16