📘 Definition of Electronegativity
Electronegativity is the tendency of an atom in a chemical bond to attract the shared pair of electrons towards itself.
It is a relative, dimensionless property and is commonly expressed using the Pauling scale.
⚛️ Electron Gain Enthalpy
Electron Gain Enthalpy (EGE) is the enthalpy change that occurs when an isolated gaseous atom gains an electron to form a gaseous negative ion.
It is an energy-related quantity and is generally expressed in kJ mol⁻¹.
🔍 Difference Between Electronegativity and EGE
| Electronegativity | Electron Gain Enthalpy |
|---|---|
| Tendency of an atom to attract shared electrons in a chemical bond. | Energy change when an isolated gaseous atom gains an electron. |
| Applies to an atom in a chemical bond. | Applies to an isolated gaseous atom. |
| It is a relative and dimensionless quantity. | It is an enthalpy/energy change. |
| Usually expressed on scales such as the Pauling scale. | Expressed in kJ mol⁻¹. |
✅ Final Answer
Electronegativity is the tendency of an atom in a chemical bond to attract the shared electron pair towards itself.
Electron Gain Enthalpy is the enthalpy change when an isolated gaseous atom gains an electron.
The main difference is that electronegativity describes the attraction for shared electrons in a bond, whereas EGE describes the energy change associated with gaining an electron by an isolated gaseous atom.
20 MCQs with Answers
1. Electronegativity is the tendency of an atom to:
✅ Answer
B) Attract shared electrons
2. Electronegativity is associated with:
✅ Answer
B) Atom in a chemical bond
3. Electronegativity is a:
✅ Answer
A) Dimensionless quantity
4. The Pauling scale is used to measure:
✅ Answer
C) Electronegativity
5. Electron Gain Enthalpy involves:
✅ Answer
B) Gain of an electron
6. EGE is generally expressed in:
✅ Answer
A) kJ mol⁻¹
7. EGE is defined for:
✅ Answer
A) An isolated gaseous atom
8. Which property is relative and dimensionless?
✅ Answer
B) Electronegativity
9. Which quantity represents an energy change?
✅ Answer
B) Electron Gain Enthalpy
10. In electronegativity, the electrons being attracted are:
✅ Answer
B) Shared/bonding electrons
11. Which element has the highest electronegativity?
✅ Answer
A) Fluorine
12. Electronegativity generally increases:
✅ Answer
B
13. Electron gain enthalpy is concerned with:
✅ Answer
B
14. Which statement is correct?
✅ Answer
C
15. The process represented by X(g) + e⁻ → X⁻(g) is related to:
✅ Answer
B
16. Electronegativity is mainly useful in understanding:
✅ Answer
A) Bond polarity
17. A highly electronegative atom strongly attracts:
✅ Answer
A
18. Which is NOT a difference between electronegativity and EGE?
✅ Answer
D
19. EGE can be positive or negative depending on:
✅ Answer
A
20. Which pair is correctly matched?
✅ Answer
C
Q. Define electronegativity and electron gain enthalpy.
Solution:
Electronegativity: The tendency of an atom in a chemical bond to attract the shared electron pair towards itself.
Electron Gain Enthalpy: The enthalpy change when an isolated gaseous atom gains an electron to form a negative ion.
Q. Differentiate between electronegativity and electron gain enthalpy.
Solution:
- Electronegativity is the tendency to attract shared electrons in a chemical bond.
- Electron gain enthalpy is the energy change when an isolated gaseous atom gains an electron.
- Electronegativity is dimensionless, whereas EGE is expressed in kJ mol⁻¹.
Q. Explain the difference between electronegativity and electron gain enthalpy with suitable points.
Solution:
| Basis | Electronegativity | Electron Gain Enthalpy |
|---|---|---|
| Meaning | Attraction for shared electrons | Energy change on gaining electron |
| Atom | Atom in a chemical bond | Isolated gaseous atom |
| Nature | Relative property | Thermodynamic quantity |
| Unit | Dimensionless | kJ mol⁻¹ |
Q. Define electronegativity. Explain how it differs from electron gain enthalpy.
Solution:
Electronegativity is the tendency of an atom in a molecule to attract the shared pair of electrons towards itself. It is a relative and dimensionless property.
Electron gain enthalpy is the enthalpy change associated with the addition of an electron to an isolated gaseous atom.
Chemical bond → Shared electrons → Relative attraction
EGE
Isolated gaseous atom → Electron added → Energy change
Thus, although both concepts are related to the tendency of atoms to attract electrons, they are not the same quantity.
Q. Define electronegativity and electron gain enthalpy. Compare their nature, conditions and significance.
1. Electronegativity
Electronegativity is the tendency of an atom in a chemical bond to attract the shared pair of electrons towards itself.
It is a relative and dimensionless quantity. The Pauling scale is commonly used to compare electronegativities of elements.
2. Electron Gain Enthalpy
Electron gain enthalpy is the enthalpy change when an isolated gaseous atom accepts an electron to form a gaseous anion.
It is an energy-related quantity and is expressed in kJ mol⁻¹. It may be negative when energy is released or positive when energy is absorbed.
3. Major Differences
| Point | Electronegativity | EGE |
|---|---|---|
| Definition | Attraction for shared electron pair | Energy change on electron gain |
| Condition | Atom in chemical bond | Isolated gaseous atom |
| Nature | Relative property | Thermodynamic quantity |
| Unit | No unit | kJ mol⁻¹ |
| Use | Helps explain bond polarity | Shows energetics of electron addition |
Electronegativity and electron gain enthalpy are related but different concepts. Electronegativity is the relative tendency of an atom in a chemical bond to attract shared electrons, while electron gain enthalpy is the actual enthalpy change associated with adding an electron to an isolated gaseous atom.
🎯 Quick Revision
Condition: Atom in chemical bond
Nature: Relative & dimensionless
EGE: Energy change on electron gain
Condition: Isolated gaseous atom
Unit: kJ mol⁻¹
