📘 Solution
All four elements belong to Group 17 (Halogens) of the periodic table.
The electronegativity of elements generally decreases down a group because atomic size and shielding effect increase.
🔍 Reason
- Down the group, the number of electron shells increases.
- Atomic size increases.
- Shielding effect increases.
- The attraction between the nucleus and shared electrons decreases.
- Therefore, electronegativity decreases down the group.
📊 Electronegativity Values (Pauling Scale)
| Element | Electronegativity |
|---|---|
| F | 3.98 |
| Cl | 3.16 |
| Br | 2.96 |
| I | 2.66 |
✅ Final Answer
Decreasing order of electronegativity:
F > Cl > Br > I
20 MCQs with Answers
1. Which halogen has the highest electronegativity?
✅ Answer
C) F
2. The correct decreasing order of electronegativity is:
✅ Answer
B) F > Cl > Br > I
3. Electronegativity down Group 17 generally:
✅ Answer
B) Decreases
4. Which element has the smallest electronegativity among F, Cl, Br and I?
✅ Answer
D) I
5. Electronegativity is the tendency to attract:
✅ Answer
C) Shared electrons
6. The most electronegative element is:
✅ Answer
B) Fluorine
7. Which factor increases down a group?
✅ Answer
B) Atomic size
8. The shielding effect down a group generally:
✅ Answer
B) Increases
9. Which has greater electronegativity?
✅ Answer
A) F
10. Chlorine is more electronegative than bromine because chlorine has:
✅ Answer
B) Smaller atomic size
11. Electronegativity is generally measured using:
✅ Answer
C) Pauling scale
12. Which order represents increasing electronegativity?
✅ Answer
C) Both A and B
13. F, Cl, Br and I belong to:
✅ Answer
C) Group 17
14. Which halogen has the largest atomic radius?
✅ Answer
D) I
15. Increase in atomic size generally causes electronegativity to:
✅ Answer
B) Decrease
16. Which has the highest attraction for a shared electron pair?
✅ Answer
A) F
17. Electronegativity generally increases:
✅ Answer
B
18. Which sequence is correct for electronegativity?
✅ Answer
A) I < Br < Cl < F
19. The decrease in electronegativity down Group 17 is mainly due to:
✅ Answer
B
20. The correct statement is:
✅ Answer
C) F is the most electronegative halogen
Q. Arrange F, Cl, Br and I in decreasing order of electronegativity.
Solution: Electronegativity decreases down Group 17 due to increase in atomic size and shielding effect.
Q. Explain the trend of electronegativity among F, Cl, Br and I.
Solution:
- F, Cl, Br and I belong to Group 17.
- Atomic size and shielding effect increase down the group.
- Therefore, attraction for shared electrons decreases.
Q. Give reasons for the decreasing order of electronegativity of F, Cl, Br and I.
Solution:
As we move from F to I down Group 17, a new electron shell is added at each step. Consequently, atomic radius and shielding effect increase. The shared electron pair becomes farther from the nucleus and experiences less effective attraction. Hence electronegativity decreases.
Q. Explain the variation of electronegativity down Group 17 with suitable examples.
Solution:
Electronegativity is the tendency of an atom in a chemical bond to attract the shared pair of electrons towards itself.
F, Cl, Br and I are members of Group 17. Down the group, the number of electron shells increases. This increases atomic size and shielding effect. As a result, the nucleus attracts the shared electron pair less strongly.
F > Cl > Br > I
Q. Explain in detail the trend in electronegativity of F, Cl, Br and I.
1. Position in the Periodic Table
F, Cl, Br and I are halogens and belong to Group 17.
2. Downward Change in Atomic Size
As we move down the group, new electron shells are added. Therefore, the atomic radius increases from F to I.
3. Increase in Shielding Effect
The number of inner-shell electrons increases down the group. These electrons shield the valence electrons from the attraction of the nucleus.
4. Decrease in Attraction
Because the shared electron pair is farther from the nucleus and more strongly shielded, the attraction for the shared electrons decreases.
↓
Nuclear Attraction for Shared Electrons ↓
↓
Electronegativity ↓
5. Final Order
Decreasing order of Electronegativity
🎯 Quick Revision
Trend: Electronegativity decreases down the group
Highest: F
Lowest: I
Order: F > Cl > Br > I
