Question 12

(a) (b ) (c) (d) (e) 218Ra -86 222Rn -> 84PO - 214 -Bi - PO What kind of particle is emitted in each of the transmutations, labelled (a) to (e)? 11. A proton strikes a sodium-20 nucleus and an alpha particle is emitted. What is the mass number and atomic number of the residual nucleus? Write an equation for the nuclear reaction. 12. The half-life of a certain radioactive isotope is 20 h. How much of an original 320 g sample will remain the same radioactive isotope after (a) 40 h? (b) 80 h? (c) 5 d