Periodic Classification and Periodic Properties 2 Question 27

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27. Ionic radii of

======= ####27. Ionic radii of

3e0f7ab6f6a50373c3f2dbda6ca2533482a77bed (a) $\mathrm{Ti}^{4+}<\mathrm{Mn}^{7+}$

(b) ${ }^{35} \mathrm{Cl}^{-}<{ }^{37} \mathrm{Cl}^{-}$

(c) $\mathrm{K}^{+}>\mathrm{Cl}^{-}$

(d) $\mathrm{P}^{3+}>\mathrm{P}^{5+}$

(1999, 3M)

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Answer:

Correct Answer: 27. (c)

Solution:

  1. (a) $\mathrm{Ti}^{4+}>\mathrm{Mn}^{7+}$ is the correct order of size due to lower positive charge on $\mathrm{Ti}^{4+}$.

(b) ${ }^{37} \mathrm{Cl}^{-}={ }^{37} \mathrm{Cl}^{-}$: Isotopes with same charge have same size because isotopes differ in compositions of nuclei which do not affect the atomic/ionic radius.

(c) $\mathrm{K}^{+}<\mathrm{Cl}^{-}$is the correct order. Among isoelectronic species, anion has greater size than cation.

(d) $\mathrm{P}^{3+}>\mathrm{P}^{5+}$ is the correct order. For the same elements, lower the positive charge, larger the ions.