Answer the question below (a)

2 A stable nucleus of an element has a certain number of protons and . neutrons. Some isotopes have stable nuclei. The isotopes of the element with a larger or smaller number of neutrons are usually unstable. (a Iodine-131 is a radioisotope of iodine. A radioisotope sample that contains ) 200g of iodine-131 undergoes a decay process. The half-life of iodine-131 is 8 days. (i) What is the meaning of half-life? (ii) Give one reason why iodine-131 undergoes a decay process. (iii) Calculate the mass of iodine-131 after 32 days. (iv) In the diagram below, sketch a graph to show the decay process of iodine-131. Mass lg) Jisim {g} 300 0 Time (days) Mam {hart l