Question

(a) What are radioactive isotopes ? Give two examples of radioactive isotopes.
(b) Give any two uses of radioactive isotopes.
(c) An element Z contains two naturally occurring isotopes Z3517 and Z3717. If the average atomic mass of this element be 35.5 u, calculate the percentage of two isotopes.

Answer 1

Answer:

(c). z3517

35z+37(100-z)/100=35.5

35z-37z+3700=35.5×100

-2z+3700=3550

-2z=3550-3700

-2z=-150

2z=150

z=150/2

z or Z=75%.

z3717 or x3717, because it is easy to understand.

37x+35(100-x)/100=35.5

37x-35x+3500=35.5×100

2x+3500=3550

2x=3550-3500

2x=50

x=50/2

x or X=25%.

Answer 2

1. Common examples of radioactive isotopes are Arsenic−74, Iodine−131 and Cobalt−60. (i) Cobalt−60 is used in the treatment of cancer cells. When the high−energy gamma radiations emitted by cobalt−60 isotopes are directed at the cancerous tumours , the cells are burnt. no
2. Radioactive isotopes have many useful applications. In medicine, for example, cobalt-60 is extensively employed as a radiation source to arrest the development of cancer. Other radioactive isotopes are used as tracers for diagnostic purposes as well as in research on metabolic processes

.