JEE Main - Periodic trends atomic and ionic radii ionization enthalpy electron gain enthalpy Question Bank with Options

1. The ionization enthalpy of Argon is significantly higher than that of Chlorine. This is due to:

A) Argon having a stable octet configuration

B) Argon being a noble gas

C) Argon having a larger atomic radius

D) Both A and B

2. Which of the following species is diamagnetic?

A) O₂⁺

B) O₂⁻

C) O₂²⁻

D) O₂

3. The electron gain enthalpy of Nitrogen is positive. This is because:

A) Nitrogen has a very stable half-filled p-subshell

B) Nitrogen has a high nuclear charge

C) Nitrogen is a non-metal

D) Nitrogen has a small atomic radius

4. Which of the following has the highest electron affinity (most negative electron gain enthalpy)?

A) S

B) Se

C) Te

D) Po

5. Consider the elements X, Y, and Z with atomic numbers 11, 12, and 13 respectively. The correct order of their atomic radii is:

A) X > Y > Z

B) Z > Y > X

C) X > Z > Y

D) Y > X > Z

6. Which factor has the least effect on the ionization enthalpy of an element?

A) Nuclear charge

B) Shielding effect

C) Penetration of electrons

D) Number of neutrons

7. The electronic configuration of an element is 1s²2s²2p⁶3s²3p³. What is the trend of its ionization enthalpy compared to the element with configuration 1s²2s²2p⁶3s¹?

A) Higher than the element with 3s¹

B) Lower than the element with 3s¹

C) Same as the element with 3s¹

D) Cannot be compared

8. The anomaly in the atomic radii trend in the third period is observed between:

A) Na and Mg

B) Al and Si

C) Ar and Cl

D) Mg and Al

9. Which of the following is an exception to the general trend of ionization enthalpy in Group 13?

A) B < Al < Ga < In

B) Al < Ga < In < Tl

C) B > Al

D) Ga < In

10. Which statement about electron gain enthalpy is INCORRECT?

A) Electron gain enthalpy generally becomes more negative across a period.

B) Electron gain enthalpy generally becomes less negative down a group.

C) Noble gases have positive electron gain enthalpies.

D) Alkaline earth metals have highly negative electron gain enthalpies.

11. Which statement about ionization enthalpy is CORRECT?

A) Ionization enthalpy increases down a group.

B) Noble gases have very low ionization enthalpies.

C) The second ionization enthalpy is always smaller than the first.

D) Elements with half-filled or fully-filled electronic configurations have exceptionally low ionization enthalpies.

12. Which statement about atomic radii is INCORRECT?

A) Atomic radius decreases across a period due to increasing effective nuclear charge.

B) Atomic radius increases down a group due to the addition of new electron shells.

C) Noble gases have larger atomic radii than halogens in the same period.

D) Cations are smaller than their parent atoms.

13. The electron gain enthalpies of Group 17 elements (halogens) generally become less negative in the order:

A) F > Cl > Br > I

B) I > Br > Cl > F

C) Cl > F > Br > I

D) F < Cl < Br < I

14. The first ionization enthalpies of Group 1 elements (alkali metals) generally decrease in the order:

A) Li > Na > K > Rb > Cs

B) Cs > Rb > K > Na > Li

C) Na > Li > K > Rb > Cs

D) Li < Na < K < Rb < Cs

15. Which of the following ions is smallest in size: K⁺, Cl⁻, S²⁻, P³⁻?

A) K⁺

B) Cl⁻

C) S²⁻

D) P³⁻

16. Which of the following sets of elements shows decreasing order of first ionization enthalpy?

A) Li > Be > B > C

B) F > O > N > C

C) Na > Mg > Al > Si

D) Ne > F > O > N

17. Which of the following sets of elements shows increasing order of atomic radii?

A) Li < Be < B < C

B) C < B < Be < Li

C) O < F < Cl < S

D) Na < Mg < Al < Si

18. The electron gain enthalpy of Fluorine is less negative than that of Chlorine. What is the reason?

A) Fluorine has a larger atomic radius

B) Fluorine has a smaller atomic radius, leading to interelectronic repulsion in the compact 2p subshell

C) Chlorine has a higher nuclear charge

D) Fluorine is more electronegative

19. Which of the following elements has a positive electron gain enthalpy?

A) Chlorine

B) Oxygen

C) Nitrogen

D) Noble gases

20. Which element has the most negative electron gain enthalpy in the second period?

A) Li

B) B

C) F

D) Ne

21. How does electron gain enthalpy generally change down a group?

A) Becomes more negative down the group

B) Becomes less negative (or more positive) down the group

C) Remains constant

D) Becomes zero

22. What is the primary reason for the trend in electron gain enthalpy across a period?

A) Decrease in nuclear charge

B) Increase in atomic radius

C) Increase in effective nuclear charge

D) Decrease in shielding effect

23. How does electron gain enthalpy generally change across a period?

A) Becomes more negative (or less positive) from left to right

B) Becomes more positive (or less negative) from left to right

C) Remains constant

D) Alternates between positive and negative

24. A negative electron gain enthalpy indicates that the atom __________.

A) readily accepts an electron

B) readily loses an electron

C) is a noble gas

D) is a metal

25. What is electron gain enthalpy?

A) Energy released when an electron is added to a neutral gaseous atom to form an anion

B) Energy required to remove an electron from a neutral gaseous atom

C) Energy required to add an electron to a neutral gaseous atom

D) Energy released when a gaseous ion gains an electron

26. The second ionization enthalpy (IE₂) is always __________ the first ionization enthalpy (IE₁).

A) less than

B) equal to

C) greater than

D) unrelated to

27. The ionization enthalpy of Boron (atomic number 5) is lower than that of Beryllium (atomic number 4). What is the reason?

A) Boron has a larger atomic radius

B) Boron has a filled s-orbital

C) The electron removed from Boron is from a 2p orbital which is higher in energy than the 2s orbital of Beryllium

D) Beryllium has a greater nuclear charge

28. Which element has the lowest first ionization enthalpy in the third period?

A) Na

B) Mg

C) Al

D) Si

29. Which element has the highest first ionization enthalpy in the second period?

A) Li

B) Be

C) B

D) Ne

30. What is the main reason for the decrease in ionization enthalpy down a group?

A) Increase in nuclear charge

B) Decrease in atomic radius

C) Increase in shielding effect of inner electrons

D) Decrease in effective nuclear charge

31. How does the first ionization enthalpy generally change down a group?

A) Increases down the group

B) Decreases down the group

C) Remains constant

D) Increases up the group

32. What is the primary reason for the increase in ionization enthalpy across a period?

A) Increase in atomic radius

B) Decrease in nuclear charge

C) Increase in effective nuclear charge

D) Decrease in electron shielding

33. How does the first ionization enthalpy generally change across a period?

A) Increases from left to right

B) Decreases from left to right

C) Remains constant

D) Increases from right to left

34. Which symbol represents the first ionization enthalpy?

A) IE₁

B) IE₂

C) EA₁

D) EA₂

35. What is ionization enthalpy?

A) Energy required to remove an electron from a neutral gaseous atom

B) Energy released when an electron is added to a neutral gaseous atom

C) Energy required to excite an electron to a higher energy level

D) Energy released when a gaseous ion gains an electron

36. Consider the isoelectronic series: O²⁻, F⁻, Na⁺, Mg²⁺. Which species has the largest ionic radius?

A) O²⁻

B) F⁻

C) Na⁺

D) Mg²⁺

37. In an isoelectronic series, how does the ionic radius change with increasing nuclear charge?

A) Increases

B) Decreases

C) Remains constant

D) Becomes zero

38. What is isoelectronic species?

A) Atoms with the same number of neutrons

B) Atoms with the same number of electrons

C) Atoms with the same number of protons

D) Atoms with the same chemical properties

39. Which ion is expected to have the smallest radius: Li⁺, Na⁺, K⁺, or Rb⁺?

A) Li⁺

B) Na⁺

C) K⁺

D) Rb⁺

40. Which ion is expected to have the largest radius: S²⁻, Cl⁻, K⁺, or Ca²⁺?

A) S²⁻

B) Cl⁻

C) K⁺

D) Ca²⁺

41. How does the ionic radius of a cation compare to its parent atom?

A) Larger than the parent atom

B) Smaller than the parent atom

C) Equal to the parent atom

D) Always zero

42. How does the ionic radius of an anion compare to its parent atom?

A) Smaller than the parent atom

B) Larger than the parent atom

C) Equal to the parent atom

D) Cannot be determined

43. What is the trend in ionic radii down a group?

A) Generally decreases

B) Generally increases

C) Remains the same

D) Fluctuates unpredictably

44. Which element is expected to have the smallest atomic radius among Li, Be, B, and C?

A) Li

B) Be

C) B

D) C

45. Which element is expected to have the largest atomic radius among Na, Mg, K, and Ca?

A) Na

B) Mg

C) K

D) Ca

46. What is the main reason for the increase in atomic radius down a group?

A) Decrease in nuclear charge

B) Addition of new electron shells

C) Decrease in effective nuclear charge

D) Increase in ionization enthalpy

47. How does atomic radius generally change down a group in the periodic table?

A) Decreases down the group

B) Increases down the group

C) Remains constant

D) Increases up the group

48. What is the primary reason for the decrease in atomic radius across a period?

A) Increase in the number of electron shells

B) Decrease in nuclear charge

C) Increase in effective nuclear charge

D) Increase in electron-electron repulsion

49. How does atomic radius generally change across a period in the periodic table?

A) Increases from left to right

B) Decreases from left to right

C) Remains constant

D) Increases from right to left

50. Which of the following factors primarily determines the atomic radius of an atom?

A) Number of neutrons

B) Number of protons

C) Distance of the outermost electron from the nucleus

D) Total number of electrons

Periodic trends atomic and ionic radii ionization enthalpy electron gain enthalpy - Question Bank