Cationic Radius

Q.

Which of the following has the largest size?

1. Al

2. $A{l}^{+}$

3. $A{l}^{2+}$

4. $A{l}^{3+}$

Q.

$N{a}^{+}.M{g}^{2+},A{l}^{3+}$ and $S{i}^{4+}$ are isoelectronic. The order of their ionic size is

1. $N{a}^{+}>M{g}^{2+}<A{l}^{3+}<S{i}^{4+}$

2. $N{a}^{+}<M{g}^{2+}>A{l}^{3+}>S{i}^{4+}$

3. $N{a}^{+}>M{g}^{2+}>A{l}^{3+}>S{i}^{4+}$

4. $N{a}^{+}<M{g}^{2+}>A{l}^{3+}<S{i}^{4+}$

Q. The ionic radii of $R{b}^{+}$ and $I^{-}$ are $1.46$ and $2.16\stackrel{\circ }{\text{A}}$. The coordination number for the cation is:

Q.

The smallest among the following ions is

1. $N{a}^{+}$

2. $M{g}^{+2}$

3. $B{a}^{2+}$

4. $A{l}^{3+}$

Q.

Ionic radii of which ions is same

1. ${}^{35}C{l}^{\ominus }>{}^{37}C{l}^{\ominus }$

2. $M{n}^{7+},T{i}^{+4}$

3. $K^{+},C{l}^{\ominus }$

4. $P^{+3},P^{+5}$

Q.

When the following five anions are arranged in order of decreasing ionic radius, the correct sequence is?

1. $S{e}^{2-},I^{-},B{r}^{-},O^{2-},F^{-}$

2. $I^{-},S{e}^{2-},O^{2-},B{r}^{-},F^{-}$

3. $S{e}^{2-},I^{-},B{r}^{-},F^{-},O^{2-}$

4. $I^{-},S{e}^{2-},B{r}^{-},O^{2-},F^{-}$

Q. Select the correct relation regarding the ionic radii of given ions:

1. $T{i}^{4+}<M{n}^{7+}$
2. ${}^{35}C{l}^{-}<{}^{37}C{l}^{-}$
3. $K^{+}>C{l}^{-}$
4. $P^{3+}>P^{5+}$

Q.

Which one of the following alkaline earth metal sulphates has its hydration enthalpy greater than its lattice enthalpy?

1. $CaS{O}_4$

2. $BeS{O}_4$

3. $BaS{O}_4$

4. $SrS{O}_4$

Q. The size of the species $I,I^{-}$ & $I^{+}$ follows the order:

1. $I>I^{-}>I^{+}$
2. $I^{+}>I>I^{-}$
3. $I^{-}>I>I^{+}$
4. $I^{+}>I^{-}>I$

Q.

If the ionic radii of $K^{+}$ and $F^{-}$ are nearly the same (i.e $1.34\mathring{A}$) then the atomic radii of $K$ and $F$ are respectively are

1. $1.34\mathring{A},1.34\mathring{A}$

2. $0.72\mathring{A},1.96\mathring{A}$

3. $1.96\mathring{A},0.72\mathring{A}$

4. $1.96\mathring{A},1.34\mathring{A}$

Q.

Which of the following has the smallest size?

1. $N{a}^{+}$

2. $M{g}^{2+}$

3. $C{l}^{-}$

4. $F^{-}$

Q.

Which of the following cations has the smallest radius?

1. $K^{+}$

2. $N{a}^{+}$

3. $L{i}^{+}$

4. $B{e}^{2+}$

Q. To determine the radii of a univalent ion, Pauling gave a method as follows:
i. In an ionic crystal of the type $M^{+}{X}^{-}$, cations and anions are in contact with each other. Therefore, the sum of their ionic radius is equal to the interionic distance.
ii. $r_M^{+}+r_X^{-}=\frac{c}{Z_{eff}\left(M^{+}\right)}+\frac{c}{Z_{eff}\left(X^{-}\right)}$ pm $Z_{eff}$ is the effective nuclear charge $Z_{eff}=Z-\sigma$ ; where $\sigma$is the screening constant. For $\text{Ne},\sigma =4.5$
$\therefore r_{\text{M}}^{+}=\frac{c}{Z_{\text{eff}}\left(M^{+}\right)}$ and $r_X^{-}=\frac{c}{Zeff\left(X^{-}\right)}$

The actual interionic distance in $MgO$ should be:

1. 256 pm
2. 276 pm
3. Lesser than 256 pm
4. 372 pm