Mulliken scale of electronegativity formula?

1. Mulliken scale of electronegativity formula? +

Correct Answer

χ_M = ½(I + A)

Formula & Meaning

The Mulliken electronegativity of an atom is defined as the average of its ionization energy (I) and electron affinity (A).

χ_M = ½(I + A)

Where:

• χ_M = Mulliken electronegativity
• I = first ionization energy
• A = electron affinity

If ionization energy and electron affinity are expressed in the same energy units, the formula can be applied directly.

Conceptual Derivation

Mulliken proposed that electronegativity should reflect two important properties of an atom: 1. Ionization Energy (I)
It represents the energy required to remove an electron. A high ionization energy means the atom holds its electrons strongly.

2. Electron Affinity (A)
It represents the tendency of an atom to accept an electron. Therefore, Mulliken defined electronegativity as their average:

χ_M = (I + A) / 2

Hence, an atom with high ionization energy and high electron affinity generally has high Mulliken electronegativity.

Important Exam Point

Do not confuse the Mulliken formula with the Pauling scale.

Mulliken: χ = ½(I + A)

Pauling: Based on bond dissociation energies.

The Mulliken scale is therefore directly related to the ionization energy and electron affinity of the atom.

Shortcut: Mulliken = Average of I.E. + E.A.

30 Related MCQs with Solutions

1. The Mulliken electronegativity is given by:

A. I − A

B. I + A

C. ½(I + A)

D. I/A

Answer: C. ½(I + A)

2. Mulliken electronegativity depends on:

A. Ionization energy only

B. Electron affinity only

C. Both ionization energy and electron affinity

D. Atomic mass only

Answer: C

3. In Mulliken's equation, I represents:

A. Ionic radius

B. Ionization energy

C. Intensity

D. Interatomic distance

Answer: B. Ionization energy

4. In Mulliken's equation, A represents:

A. Atomic radius

B. Electron affinity

C. Atomic mass

D. Area

Answer: B. Electron affinity

5. Mulliken electronegativity is essentially the:

A. Difference between I and A

B. Average of I and A

C. Product of I and A

D. Ratio of I and A

Answer: B

6. If I = 10 eV and A = 2 eV, Mulliken electronegativity is:

A. 4 eV

B. 5 eV

C. 6 eV

D. 12 eV

Answer: B. 6 eV
Calculation: (10 + 2)/2 = 6 eV.

7. If I = 8 eV and A = 4 eV, χ_M equals:

A. 2 eV

B. 4 eV

C. 6 eV

D. 12 eV

Answer: C. 6 eV

8. Higher Mulliken electronegativity generally indicates:

A. Weak attraction for electrons

B. Greater tendency to attract electrons

C. Metallic character only

D. Larger atomic radius

Answer: B

9. Which two properties are averaged in Mulliken's scale?

A. Atomic radius and mass

B. Ionization energy and electron affinity

C. Density and melting point

D. Atomic number and mass

Answer: B

10. Which scale is directly based on ionization energy and electron affinity?

A. Mulliken

B. Pauling

C. Allred-Rochow

D. Allen

Answer: A. Mulliken

11. If both I and A increase, Mulliken electronegativity generally:

A. Decreases

B. Increases

C. Becomes zero

D. Remains unchanged

Answer: B

12. If I = 12 eV and A = 6 eV, χ_M is:

A. 3 eV

B. 6 eV

C. 9 eV

D. 18 eV

Answer: C. 9 eV

13. Mulliken electronegativity is associated with:

A. Gas pressure

B. Atomic electronic properties

C. Crystal density only

D. Nuclear mass only

Answer: B

14. Which quantity measures the energy needed to remove an electron?

A. Electron affinity

B. Ionization energy

C. Electronegativity

D. Bond energy

Answer: B

15. Which quantity describes the tendency of an atom to accept an electron?

A. Electron affinity

B. Ionization energy

C. Atomic radius

D. Ionization potential only

Answer: A

16. Mulliken's formula can be written as:

A. χ = I − A

B. χ = (I + A)/2

C. χ = 2(I + A)

D. χ = I × A

Answer: B

17. If I = 14 eV and A = 10 eV, χ_M is:

A. 2 eV

B. 7 eV

C. 12 eV

D. 24 eV

Answer: C. 12 eV

18. Which statement is correct?

A. Mulliken scale uses only bond energies

B. Mulliken scale uses I.E. and E.A.

C. Mulliken scale uses atomic mass

D. Mulliken scale ignores electron affinity

Answer: B

19. Which scale is based on bond dissociation energies?

A. Mulliken

B. Pauling

C. None

D. Both exclusively

Answer: B. Pauling

20. If I = 20 eV and A = 4 eV, χ_M is:

A. 8 eV

B. 10 eV

C. 12 eV

D. 24 eV

Answer: C. 12 eV

21. Mulliken electronegativity is higher when:

A. I and A are both relatively high

B. I and A are both zero

C. Only atomic mass is high

D. Atomic radius is very large

Answer: A

22. The factor ½ in Mulliken's equation represents:

A. Difference

B. Average

C. Product

D. Ratio

Answer: B

23. If I = A = 10 eV, then χ_M equals:

A. 5 eV

B. 10 eV

C. 20 eV

D. 100 eV

Answer: B. 10 eV

24. Mulliken electronegativity is fundamentally a measure of:

A. Electron-attracting tendency

B. Neutron-attracting tendency

C. Nuclear size

D. Atomic mass

Answer: A

25. Which value is required along with ionization energy in Mulliken's formula?

A. Atomic radius

B. Electron affinity

C. Atomic mass

D. Density

Answer: B

26. If I = 16 eV and A = 8 eV, χ_M equals:

A. 4 eV

B. 8 eV

C. 12 eV

D. 24 eV

Answer: C. 12 eV

27. Which statement about Mulliken electronegativity is true?

A. It is the arithmetic mean of I and A

B. It is the geometric mean of I and A

C. It is I − A

D. It is I/A

Answer: A

28. If ionization energy increases while electron affinity remains constant, Mulliken electronegativity:

A. Increases

B. Decreases

C. Becomes zero

D. Is unaffected

Answer: A

29. Mulliken's scale connects electronegativity with:

A. I.E. and E.A.

B. Atomic radius and density

C. Melting and boiling points

D. Nuclear mass and volume

Answer: A

30. The correct Mulliken electronegativity formula is:

A. χ = I − A

B. χ = I × A

C. χ = ½(I + A)

D. χ = I/A

Answer: C. χ = ½(I + A)

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