30 MCQS on Isotopes and Isotopes

Here are 30 multiple-choice questions (MCQs) on Isotopes and Isotones, specifically tailored for CSIR NET Life Science preparation:

Section 1: Basics of Isotopes and Isotones

1. Isotopes are atoms of the same element that have the same:

a) Number of protons but different number of neutrons

b) Number of neutrons but different number of protons

c) Number of electrons but different atomic numbers

d) Mass number and atomic number

2. Which of the following statements about isotopes is correct?

a) They have the same physical properties

b) They have identical chemical properties

c) Their atomic masses are the same

d) They always undergo radioactive decay

3. The isotopes of an element have the same:

a) Atomic number

b) Mass number

c) Neutron number

d) Chemical reactivity

4. Which of the following elements has naturally occurring isotopes?

a) Carbon

b) Hydrogen

c) Oxygen

d) All of the above

5. Which of the following is NOT an isotope of Hydrogen?

a) Protium

b) Deuterium

c) Tritium

d) Helium

6. Isotones are atoms of different elements that have:

a) The same number of neutrons

b) The same number of protons

c) The same atomic number

d) The same mass number

7. Which of the following pairs represents isotones?

a) Carbon-14 and Nitrogen-15

b) Oxygen-16 and Fluorine-19

c) Hydrogen-2 and Helium-4

d) Uranium-238 and Thorium-234

8. Which of the following is an application of isotopes in biology?

a) Radioactive dating

b) Medical imaging

c) Tracing metabolic pathways

d) All of the above

Section 2: Radioactive Isotopes and Their Applications

9. Carbon-14 is commonly used in:

a) PET scans

b) Radiocarbon dating

c) Cancer therapy

d) Tracing oxygen in respiration

10. Which isotope is used in thyroid function testing?

a) Carbon-14

b) Iodine-131

c) Oxygen-18

d) Strontium-90

11. Radioactive isotopes are used in:

a) Cancer treatment

b) Agriculture

c) Drug metabolism studies

d) All of the above

12. Which isotope is used in PET (Positron Emission Tomography) scans?

a) Fluorine-18

b) Iodine-125

c) Uranium-238

d) Hydrogen-3

13. Deuterium is used in:

a) Nuclear reactors

b) Labeling molecules in biological studies

c) Both a and b

d) None of the above

14. Which isotope is commonly used for metabolic tracer studies?

a) Carbon-13

b) Oxygen-16

c) Nitrogen-14

d) Hydrogen-1

15. Stable isotopes are useful in studying:

a) Protein structures

b) Photosynthesis pathways

c) Nitrogen cycles

d) All of the above

Section 3: Isotope Chemistry and Biological Importance

16. The isotope of Carbon used in tracing metabolic pathways is:

a) Carbon-12

b) Carbon-13

c) Carbon-14

d) Carbon-15

17. The isotope Oxygen-18 is used to study:

a) Water uptake in plants

b) DNA synthesis

c) Protein folding

d) Radiation therapy

18. Which isotope is used in Mössbauer spectroscopy?

a) Iron-57

b) Carbon-12

c) Oxygen-16

d) Iodine-131

19. Which isotope is used in radiopharmaceuticals?

a) Technetium-99m

b) Uranium-235

c) Hydrogen-2

d) Helium-4

20. Isotopic fractionation is useful in:

a) Climate change studies

b) Studying enzyme kinetics

c) Paleontology

d) All of the above

Section 4: Isotopes, Isotones & Nuclear Stability

21. Which isotope of uranium is used as fuel in nuclear reactors?

a) Uranium-238

b) Uranium-235

c) Uranium-234

d) Thorium-232

22. Which isotope is commonly used to determine the age of rocks?

a) Carbon-14

b) Potassium-40

c) Iodine-131

d) Hydrogen-3

23. Which of the following is an artificial isotope?

a) Carbon-14

b) Plutonium-239

c) Hydrogen-2

d) Nitrogen-14

24. Isotopic labeling is widely used in:

a) DNA sequencing

b) Protein analysis

c) Enzyme activity studies

d) All of the above

25. The isotone pair among the following is:

a) Calcium-40 and Scandium-41

b) Oxygen-18 and Carbon-14

c) Helium-4 and Lithium-7

d) Uranium-238 and Lead-206

26. Which element has isotopes with different radioactive decay patterns?

a) Carbon

b) Hydrogen

c) Uranium

d) All of the above

27. What makes an isotope unstable?

a) Excess of neutrons

b) Deficiency of neutrons

c) High neutron-to-proton ratio

d) All of the above

28. Which isotope of hydrogen is radioactive?

a) Protium

b) Deuterium

c) Tritium

d) All are stable

29. Nitrogen-15 and Oxygen-16 are considered:

a) Isotones

b) Isotopes

c) Isobars

d) None of the above

30. Which of the following pairs are NOT isotones?

a) Argon-40 and Potassium-39

b) Carbon-14 and Nitrogen-15

c) Oxygen-16 and Fluorine-17

d) Hydrogen-2 and Helium-4

Answer Key:-

1-a, 2-b, 3-a, 4-d, 5-d, 6-a, 7-a, 8-d, 9-b, 10-b, 11-d, 12-a, 13-c, 14-a, 15-d,

16-c, 17-a, 18-a, 19-a, 20-d, 21-b, 22-b, 23-b, 24-d, 25-a, 26-d, 27-d, 28-c, 29-a, 30-d.