## Classification of Elements and Periodicity in Properties Questions and Answers Part-3

1. The correct order of radii is
a) N < Be < B
b) $F^{-} < O^{2-} < N^{3-}$
c) N < Li < K
d) $Fe^{3+} < Fe^{2+} < Fe^{4+}$

Explanation: $F^{-} < O^{2-} < N^{3-}$

2. Which of the following is the smallest cation?
a) $Na^{+}$
b) $Mg^{2+}$
c) $Ca^{2+}$
d) $Al^{3+}$

Explanation: $Al^{3+}$

3. The ionic radii of $N^{3-}, O^{2-}, F^{-},and Na^{+}$   are in the order
a) $N^{3-} > O^{2-} > F^{-} > Na^{+}$
b) $N^{3-} > Na^{+} > O^{2-} > F^{-}$
c) $Na^{+} > O^{2-} > N^{3-} > F^{-}$
d) $O^{2-} > F^{-} > Na^{+} > N^{3-}$

Explanation: $N^{3-} > O^{2-} > F^{-} > Na^{+}$

a) $Ti^{4+} < Mn^{2+}$
b) $35_{CI^{-}} < 37_{CI^{-}}$
c) $K^{+}>CI^{-1}$
d) $P^{3+}>P^{5+}$

Explanation: $P^{5+}$ has more effective nuclear charge and smaller size than $P^{3+}$

5. The radii of F, F-, O and O2- are in the order
a) $O^{2-}>F^{-}>F>O$
b) $F^{-}>O^{2-}>F>O$
c) $O^{2-}>O>F^{-}>F$
d) $O^{2-}>F^{-}>O>F$

Explanation: $O^{2-}>F^{-}>O>F$

6. Which stable nucleus has radius half than that of $^{54}Xe$
a) $^{40}Ca$
b) $^{23}Na$
c) $^{32}S$
d) $^{7}Li$

Explanation: $^{32}S$

7. For which of the following ionic species radius would be maximum?
a) $C^{4-}$
b) $N^{3-}$
c) $O^{2-}$
d) $Mg^{2+}$

Explanation: Among the isoelectronic species, the anion having more negative charge would be the largest

8. The decreasing order of the size of the following ions is
a) $Li^{+}>H^{+}>H^{-}$
b) $H^{+}>H^{-}>Li^{+}$
c) $H^{-}>Li^{+}>H^{+}$
d) $H^{-}>H^{+}>Li^{+}$

Explanation: $H^{-}>Li^{+}>H^{+}$

9. Chloride ion and potassium ion are isoelectronic. Then
a) their sizes are same
b) $CI^{-}$ ion is bigger than $K^{+}$ ion
c) $K^{+}$ ion is relatively bigger
d) their sizes depend on either cation or anion

Explanation: $CI^{-}$ ion is bigger than $K^{+}$ ion
a) $Na^{+}$
b) $Mg^{2+}$
c) $Al^{3+}$
d) $P^{5+}$
Explanation: $P^{5+}$