Advertisements
Advertisements
प्रश्न
Explain the Pauling method for the determination of ionic radius.
Advertisements
उत्तर
- Ionic radius is defined as the distance from the center of the nucleus of the ion up to which it exerts its influence on the electron cloud of the ion.
- Ionic radius of the uni-univalent crystal can be calculated from the inter-ionic distance between the nuclei of the cation and anion.
- Pauling assumed that ions present in a crystal lattice are perfect spheres and they are in contact with each other, therefore d = `"r"_("C"^+) + "r"_("A"^-)` …………..(1)
Where, d = distance between the center of the nucleus of cation C+ and the anion A-. `"r"_("C"^+)` = radius of cation and `"r"_("A"^-)` = radius of the anion. - Pauling assumed that the radius of the ion having noble gas configuration (Na+ and F– having 1s2, 2s2, 2p6 configuration) is inversely proportional to the effective nuclear charge felt at the periphery of the ion.
i.e. `"r"_("C"^+) α 1/(("Z"_"eff")_("C"^+))` .........(2)
`"r"_("A"^-) α 1/(("Z"_"eff")_("A"^-))` .........(3)
Where Zeff is the effective nuclear charge
Zeff = Z – S - Dividing the equation (2) by (3)
`"r"_("C"^+)/("r"_("A"^-)) = (("Z"_"eff")_("A"^-))/(("Z"_"eff")_("C"^+))` ......(4)
On solving equation (1) and (4), the values of `"r"_("C"^+)` and `"r"_("A"^-)` can be obtained.
APPEARS IN
संबंधित प्रश्न
The group of elements in which the differentiating electron enters the anti penultimate shell of atoms are called ________.
In the third period the first ionization potential is of the order.
Which one of the following arrangements represent the correct order of least negative to most negative electron gain enthalpy
Which one of the following is the least electronegative element?
IE1 and IE2 of Mg are 179 and 348 kcal mol−1 respectively. The energy required for the reaction \[\ce{Mg -> Mg^2+ + 2e^-}\] is
In a given shell the order of screening effect is
Which one of the following is true about metallic character when we move from left to right in a period and top to bottom in a group?
How would you explain the fact that the second ionisation potential is always higher than the first ionisation potential?
Explain the following, give an appropriate reason.
The formation of \[\ce{F^-_{(g)}}\] from \[\ce{F_{(g)}}\] is exothermic while that of \[\ce{O^2-_{(g)}}\] from \[\ce{O_{(g)}}\] is endothermic.
State the trends in the variation of electronegativity in groups and periods.
