Periodic Classification and Periodic Properties - Result Question 30
####27. Ionic radii of
(a) $Ti^{4+}<Mn^{7+}$
(b) ${ }^{35} Cl^{-}<{ }^{37} Cl^{-}$
(c) $K^{+}>Cl^{-}$
(d) $P^{3+}>P^{5+}$
(1999, 3M)
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Answer:
Correct Answer: 27. (c)
Solution:
- (a) $Ti^{4+}>Mn^{7+}$ is the correct order of size due to lower positive charge on $Ti^{4+}$.
(b) ${ }^{37} Cl^{-}={ }^{37} Cl^{-}$: Isotopes with same charge have same size because isotopes differ in compositions of nuclei which do not affect the atomic/ionic radius.
(c) $K^{+}<Cl^{-}$is the correct order. Among isoelectronic species, anion has greater size than cation.
(d) $P^{3+}>P^{5+}$ is the correct order. For the same elements, lower the positive charge, larger the ions.
