Atomic and ionic radii — practice questions

Question 1 · difficulty L2 · understanding

In period 4 of the periodic table, the elements with highest and lowest atomic radii are respectively.

• A. Rb & Br
• B. Na & Cl
• C. $\mathrm{K} \& \mathrm{Br}$
• D. $\mathrm{K} \& \mathrm{Se}$

Question 2 · difficulty L2 · understanding

Choose the incorrect trend in the atomic radii (r) of the elements.

• A. r Rb < r Cs
• B. r At < r Cs
• C. r Br < r K
• D. r Mg < r Al

Question 3 · difficulty L2 · understanding

The property/properties that show irregularity in first four elements of group-17 is/are (A) Covalent radius (B) Electron affinity (C) Ionic radius (D) First ionization energy Choose the correct answer from the options given below :

• A. A, B, C and D
• B. A and C only
• C. B only
• D. B and D only

Question 4 · difficulty L2 · understanding

Given below are two statements : Statement I : The metallic radius of $$\mathrm{Na}$$ is $$1.86 \mathrm{~A}^{\circ}$$ and the ionic radius of $$\mathrm{Na}^{+}$$ is lesser than $$1.86 \mathrm{~A}^{\circ}$$ Statement II : Ions are always smaller in size than the corresponding elements. In the light of the above statements, choose the correct answer from the options given below :

• A. Both Statement I and Statement II are true
• B. Statement I is incorrect but Statement II is true
• C. Both Statement I and Statement II are false
• D. Statement I is correct but Statement II is false

Question 5 · difficulty L2 · understanding

The statement(s) that are correct about the species $$\mathrm{O}^{2-}, \mathrm{F}^{-}, \mathrm{Na}^{+}$$ and $$\mathrm{Mg}^{2+}$$. (A) All are isoelectronic (B) All have the same nuclear charge (C) $$\mathrm{O}^{2-}$$ has the largest ionic radii (D) $$\mathrm{Mg}^{2+}$$ has the smallest ionic radii Choose the most appropriate answer from the options given below :

• A. (C) and (D) only
• B. (A), (C) and (D) only
• C. (B), (C) and (D) only
• D. (A), (B), (C) and (D)

Question 6 · difficulty L2 · understanding

The correct increasing order of the ionic radii is

• A. $$\mathrm{Cl^- < Ca^{2+} < K^+ < S^{2-}}$$
• B. $$\mathrm{K^+ < S^{2-} < Ca^{2+} < Cl^-}$$
• C. $$\mathrm{Ca^{2+} < K^+ < Cl^- < S^{2-}}$$
• D. $$\mathrm{S^{2-} < Cl^- < Ca^{2+} < K^+}$$

Question 7 · difficulty L2 · understanding

Given below are two statements : one is labelled as Assertion (A) and the other is labelled as Reason (R). Assertion (A) : The ionic radii of O 2$$-$$ and Mg 2+ are same. Reason (R) : Both O 2$$-$$ and Mg 2+ are isoelectronic species. In the light of the above statements, choose the correct answer from the options given below.

• A. Both (A) and (R) are true and (R) is the correct explanation of (A).
• B. Both (A) and (R) are true but (R) is not the correct explanation of (A).
• C. (A) is true but (R) is false.
• D. (A) is false but (R) is true.

Question 8 · difficulty L2 · understanding

The correct order of ionic radii for the ions, P 3$$-$$ , S 2$$-$$ , Ca 2+ , K + , Cl $$-$$ is :

• A. P 3$$-$$ > S 2$$-$$ > Cl $$-$$ > K + > Ca 2+
• B. Cl $$-$$ > S 2$$-$$ > P 3$$-$$ > Ca 2+ > K +
• C. P 3$$-$$ > S 2$$-$$ > Cl $$-$$ > Ca 2+ > K +
• D. K + > Ca 2+ > P 3$$-$$ > S 2$$-$$ > Cl $$-$$

Question 9 · difficulty L2 · understanding

Given below are two statements : one is labelled as Assertion (A) and the other is labelled as Reason (R). Assertion (A) : Barium carbonate is insoluble in water and is highly stable. Reason (R) : The thermal stability of the carbonates increases with increasing cationic size.

• A. Both (A) and (R) are true and (R) is the true explanation of (A)
• B. (A) is true but (R) is false
• C. Both (A) and (R) are true but (R) is not the true explanation of (A)
• D. (A) is false but (R) is true.

Question 10 · difficulty L2 · understanding

The ionic radii of F $$-$$ and O 2$$-$$ respectively are 1.33$$\mathop A\limits^o$$ and 1.4$$\mathop A\limits^o$$, while the covalent radius of N is 0.74$$\mathop A\limits^o$$. The correct statement for the ionic radius of N 3$$-$$ from the following is :

• A. It is smaller than F $$-$$ and N
• B. It is bigger than O2 $$-$$ and F $$-$$
• C. It is bigger than F $$-$$ and N, but smaller than of O 2$$-$$
• D. It is smaller than O 2$$-$$ and F $$-$$ , but bigger than of N