Question

Paulings scale application formula and questions related to electronegativity using pauling scale

Answer 1

Pauling defined electronegativity of an atom as the tendency of the atom to attract electronstowards itself when combined in a compound . It is a uniteless and dimensionless quantity. Before we proceed for the formula we should analyse the factors on which electronegativity depends.

• It decreases when radius increases.
• It increases when Z eff. increases.
• It decreases when σ (shielding constant) increases.
• It increases when the oxidation state of an element increases .
• It increases as much the percentage of ‘s’ character in hybrid orbital increases .

Pauling Scale:

Is an important approach for obtaining the values of electronegativity::

Bases upon energy calculation and the expression is:

xᵤ ~ xᵥ = 0.102√(∆ᵤ-ᵥ) (expressed in KJ/mol. )

xᵤ ~ xᵥ = 0.208√(∆ᵤ-ᵥ) (expressed in Kcal/mol.)

where xᵤ is the electronegativity of U(any atom)

and xᵥ is the electronegativity of V (any atombonded to U).

∆ᵤ-ᵥ is the Resonance bond energy of U—V =

| Eᵤ-ᵥ(Observed) - Eᵤ-ᵥ(theoretical) |

Eᵤ-ᵥ(theoretical) = √(Eᵤ-ᵤ × Eᵥ-ᵥ)

The values of electronegativity in Pauling scale for different elements =

1. F = 4
2. O =3.5
3. Cl = 3.16
4. N = 3.04
5. Br = 2.85
6. I = 2.55
7. S = 2.58
8. C = 2.5
9. P = 2.18
10. H = 2.1
11. B = 2.04
12. Si = 1.8

(question related to electronegativity using pauling scale)

Pauling’s electro negativity values for elements are useful in predicting

1. Options

   (a) Polarity of the molecules
   (b) Position in the E.M.F. series
   (c) Coordination numbers
   (d) Dipole moments

   Correct Answer:

   Polarity of the molecules

   Explanation:

   Pauling scale of electronegativity was helpfulin predicting(i)Nature of bond between two atoms(ii)Stability of bondby calculating the difference in electro-negativities polarity of bond can becalculated.