Answer to Question #130616 in Physical Chemistry for Suchi

Question

(a) The first ionisation energies of silicon and sulphur are lower than that of phosphorus.
Explain.
(b) Explain the use of cation to anion radius ratio.
(c) Arrange the following according to the increasing order of covalence:
NaF, NaCl, NaBr, NaI

Answer 1

a)

Phosphorus have half field configuration . phosphorus have extra stability due to half filled

so phosphorus have heigher first ionisation energy than S , AND Si .

b).

Cation-anion radius ration which sometimes also called a radius ratio. it is ration of ionic radius of cation to anion in any cation-anion compound.

Explanation:

Cation-anion radius ration which sometimes also called a radius ratio. it is ration of ionic radius of cation to anion in any cation-anion compound. it is given as

where   is the ionic radius of cation while  is the ionic radius of the anion.

The significance of this ratio is to lie in the arrangement of ions in the crystal. it also helps in determining the coordination number of compounds.

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c) incresing order of covalence .

NaI > NaBr > NaCl > NaF .

Due to higher size of I . NaI Have higher covalent charector . than NaBr , NaCl ,