Electronegativity of an element depends on?

1. Electronegativity of an element depends on? +

Correct Answer

Effective nuclear charge, atomic size, and shielding effect

Detailed Explanation

Electronegativity is the tendency of an atom in a chemical bond to attract the shared electron pair towards itself. It mainly depends on how strongly the nucleus can attract the bonding electrons. The important factors are:

Electronegativity ∝ Effective nuclear charge

and

Electronegativity ∝ 1 / Atomic size

The major factors are: 1. Effective Nuclear Charge (Z_eff)
A higher effective nuclear charge attracts the bonding electron pair more strongly, increasing electronegativity. 2. Atomic Radius
Smaller atomic size means the bonding electrons are closer to the nucleus, so attraction is stronger and electronegativity is higher. 3. Shielding Effect
Inner-shell electrons shield the valence electrons from the nucleus. Greater shielding reduces the effective nuclear attraction and generally decreases electronegativity.

Periodic Trend

Across a period:

Electronegativity ↑ → from left to right

This happens mainly because effective nuclear charge increases and atomic radius decreases. Down a group:

Electronegativity ↓ → from top to bottom

This happens because atomic size and shielding effect increase.

Example

Consider Period 2:

C < N < O < F

Fluorine has the highest electronegativity because it has a small atomic size and a high effective nuclear attraction.

F = Most electronegative element

JEE / NEET Shortcut

Remember:

High Z_eff + Small Size + Low Shielding → High Electronegativity

Low Z_eff + Large Size + High Shielding → Low Electronegativity

Therefore, electronegativity is not determined by atomic number alone.

30 Related MCQs with Solutions

1. Electronegativity mainly depends on:

A. Atomic mass only

B. Effective nuclear charge and atomic size

C. Number of neutrons only

D. Melting point

Answer: B
Effective nuclear charge and atomic size strongly influence the attraction for bonding electrons.

2. Electronegativity increases when effective nuclear charge:

A. Decreases

B. Increases

C. Becomes zero

D. Remains unchanged

Answer: B

3. Electronegativity generally increases across a period because:

A. Atomic radius increases

B. Effective nuclear charge increases

C. Shielding increases greatly

D. Number of shells increases

Answer: B

4. Electronegativity generally decreases down a group due mainly to:

A. Decreasing atomic size

B. Increasing atomic size and shielding

C. Increasing electronegativity of inner electrons

D. Decreasing number of shells

Answer: B

5. Which factor increases electronegativity?

A. Large atomic radius

B. High shielding

C. High effective nuclear charge

D. More electron shells

Answer: C

6. Smaller atomic radius generally results in:

A. Lower electronegativity

B. Higher electronegativity

C. Zero electronegativity

D. No effect

Answer: B

7. Shielding effect causes electronegativity to:

A. Increase

B. Decrease

C. Become infinite

D. Remain exactly constant

Answer: B

8. Which element has the highest electronegativity?

A. C

B. N

C. O

D. F

Answer: D. F

9. Electronegativity is the tendency to attract:

A. Neutrons

B. Protons

C. Shared bonding electrons

D. Nuclei

Answer: C

10. Which combination gives higher electronegativity?

A. Large size + high shielding

B. Small size + high effective nuclear charge

C. Large size + low nuclear charge

D. Many shells + high shielding

Answer: B

11. Effective nuclear charge is related to:

A. Nuclear attraction experienced by an electron

B. Atomic mass only

C. Number of neutrons only

D. Melting point

Answer: A

12. Which has greater electronegativity?

A. C

B. N

C. Both equal

D. Cannot determine

Answer: B. N

13. Which has greater electronegativity?

A. O

B. N

C. C

D. B

Answer: A. O

14. Which has the highest electronegativity among Period 2 elements?

A. Li

B. C

C. O

D. F

Answer: D. F

15. Down a group, atomic radius generally:

A. Decreases

B. Increases

C. Becomes zero

D. Remains unchanged

Answer: B

16. Greater atomic radius generally causes:

A. Higher electronegativity

B. Lower electronegativity

C. No possible change

D. Infinite electronegativity

Answer: B

17. Which is generally more electronegative?

A. Na

B. Mg

C. Cl

D. K

Answer: C. Cl

18. Which periodic trend is correct?

A. EN decreases across a period

B. EN increases across a period

C. EN always remains constant

D. EN increases down every group

Answer: B

19. Which periodic trend is generally correct down a group?

A. EN increases

B. EN decreases

C. EN becomes infinite

D. EN becomes zero for all atoms

Answer: B

20. Which factor shields valence electrons from the nucleus?

A. Inner-shell electrons

B. Neutrons only

C. Protons only

D. Bonding pairs only

Answer: A

21. High shielding generally causes effective nuclear attraction to:

A. Increase

B. Decrease

C. Become infinite

D. Become exactly zero

Answer: B

22. Which has higher electronegativity, F or Cl?

A. F

B. Cl

C. Equal

D. Neither

Answer: A. F

23. Which factor is least directly responsible for periodic electronegativity trends?

A. Atomic radius

B. Effective nuclear charge

C. Shielding effect

D. Neutron number alone

Answer: D

24. Electronegativity is generally highest toward which region of the periodic table?

A. Bottom-left

B. Top-right

C. Bottom-right

D. Centre only

Answer: B

25. Which element is generally the most electronegative?

A. Oxygen

B. Fluorine

C. Chlorine

D. Nitrogen

Answer: B. Fluorine

26. Increasing effective nuclear charge generally results in:

A. Lower attraction for bonding electrons

B. Higher attraction for bonding electrons

C. Larger atomic radius only

D. Lower nuclear attraction

Answer: B

27. Which order represents increasing electronegativity?

A. F < O < N < C

B. C < N < O < F

C. O < C < N < F

D. N < C < F < O

Answer: B

28. Which combination generally gives low electronegativity?

A. Small size + high Z_eff

B. Large size + high shielding

C. Small size + low shielding

D. High nuclear attraction + small radius

Answer: B

29. Which statement is correct?

A. Electronegativity depends only on atomic mass

B. Electronegativity depends on effective nuclear charge, size and shielding

C. Electronegativity is independent of atomic size

D. Shielding always increases electronegativity

Answer: B

30. The best summary of factors affecting electronegativity is:

A. High Z_eff + small size → high EN

B. Low Z_eff + large size → high EN

C. High shielding always increases EN

D. Atomic mass alone determines EN

Answer: A

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