Covalent radius of 82 Pb is 1 . 53 A o . Calculate its electronegativity at the Alfred-Rochow scale:

Alfred-Rochow scale of electronegativity measures the electrostatic force of attraction, acting between the nucleus and the valence electrons of an atom. The most electronegative atom is fluorine. The Alfred-Rochow scale of electronegativity ( χ ) for an element is given by the formula: χ AR = 0 . 744 + 0 . 359 × Z eff r 2 . where, Z eff is the effective nuclear charge acting on the valence electrons; r is the covalent radius of the atom. The formula for the effective nuclear charge is given as: Z eff = Atomic Number ( Z ) - Shielding Factor ( σ ) . If n is taken as the ultimate shell, and ( n - 1 ) is taken as the penultimate shell, then the rules for calculating the effective nuclear charge according to Slater's rule, go as follows: The shielding factor of ns and np electrons is 0 . 35 each. The shielding factor of ( n - 1 ) s and ( n - 1 ) p electrons is 0 . 85 each. The shielding factor of lower shell s and p electrons is 1 . 00 each. The shielding factor of nd and nf electrons is 0 . 35 each. The shielding factor of all the lower shell electrons is 1 . 00 each. The electronic configuration of Pb 82 is: 1 s 2 , 2 s 2 2 p 6 , 3 s 2 3 p 6 3 d 10 , 4 s 2 4 p 6 4 d 10 4 f 14 , 5 s 2 5 p 6 5 d 10 , 6 s 2 6 p 2 . Total number of s and p electrons in the 6 th ( nth ) shell = 4 . ⇒ Screening factor = 4 × 0 . 35 = 1 . 4 . Total number of s and p electrons in the 5 th [ ( n - 1 ) th ] shell = 8 . ⇒ Screening factor = 8 × 0 . 85 = 6 . 8 . Total number of lower shell s and p electrons = 26 . ⇒ Screening factor = 1 . 00 × 26 = 26 . Total number of d and f electrons in the 6 th ( nth ) shell = 0 . Total number of d and f electrons in the lower shells = 44 . ⇒ Screening factor = 1 . 00 × 44 = 44 . ∴ Total screening effect of all the electrons in an atom of Pb = 1 . 4 + 6 . 8 + 26 + 44 = 78 . 2 . Z eff = 82 - 78 . 2 = 3 . 8 . The value of r is given as 1 . 53 A o . Putting the values in the Alfred-Rochow scale, we get: ∴ χ Pb AR = 0 . 744 + 0 . 359 × 3 . 8 ( 1 . 53 ) 2 = 1 . 32 . When the difference in the electronegativity between the two atoms increases, then the polarity of the bond also increases.

EASY

Earn 100

State Mulliken's scale for electronegativity.

Important Questions on Periodicity

HARD

Chemistry>Inorganic Chemistry>Periodicity>Electronegativity and its Applications

Among alkali metals, which element do you expect to be least electronegative and why?

HARD

Chemistry>Inorganic Chemistry>Periodicity>Electronegativity and its Applications

The ionisation potential and electron affinity of fluorine are

17.42 eV

and

3.45 eV

respectively. Calculate the electronegativity of fluorine on the Mulliken scale and the Pauling scale:

HARD

Chemistry>Inorganic Chemistry>Periodicity>Electronegativity and its Applications

Which of the following elements have the similar value of electronegativity?

MEDIUM

Chemistry>Inorganic Chemistry>Periodicity>Electronegativity and its Applications

Correct order of Pauling's electronegativity

HARD

Chemistry>Inorganic Chemistry>Periodicity>Electronegativity and its Applications

Calculate the electronegativity of carbon at Pauling's scale?

Given:

$E_{H - H} = 104.2 kcal {mol}^{- 1}$

$E_{C - C} = 83.1 kcal {mol}^{- 1}$

$E_{C - H} = 98.8 kcal {mol}^{- 1}$

Electronegativity of hydrogen $= 2.1$

HARD

Chemistry>Inorganic Chemistry>Periodicity>Electronegativity and its Applications

Select the correct statement(s).

EASY

Chemistry>Inorganic Chemistry>Periodicity>Electronegativity and its Applications

What is the difference between electronegativity and electron gain enthalpy?

MEDIUM

Chemistry>Inorganic Chemistry>Periodicity>Electronegativity and its Applications

Ionisation energies of atoms A and B are

400

and

300

k cal mol^-1 respectively. The electron affinities of these atoms are

80.0

and

85.0

k cal mol^-1 respectively. Then which is the correct statement regarding electronegativity

χ ?

HARD

Chemistry>Inorganic Chemistry>Periodicity>Electronegativity and its Applications

Covalent radius of

_{82} Pb

1.53 \overset{o}{A}

. Calculate its electronegativity at the Alfred-Rochow scale:

EASY

Chemistry>Inorganic Chemistry>Periodicity>Electronegativity and its Applications

If the ionization enthalpy and electron gain enthalpy of an element are 275 and 86 kcal mol^-1respectively, then the electronegativity of the element on the Pauling scale is:

MEDIUM

Chemistry>Inorganic Chemistry>Periodicity>Electronegativity and its Applications

Correct order of electronegativity of