Vanderwaal Radius

Q.

The atomic radius in case of inert gasses is?

1. Ionic radius

2. Covalent radius

3. Vander Waals radius

4. None

Q. Which of the following elements has the largest Van der Waals radii?

1. $Ne$

2. $Cl$

3. $O$

4. $F$

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 $r_X^{-}=\frac{C}{Zeff\left(X^{-}\right)}$

In $\text{NaF}$ crystal, $r_{Na}^{+}+r_F^{-}=230$ pm therefore, the radius of $F^{-}$ is

1. 136 pm
2. 94.5 pm
3. 112 pm
4. 115 pm

Q.

Atomic radic of fluorine and neon in $\mathring{A}$ units are respectively given by

1. 0.72, 160

2. 1.60 , 1.60

3. 0.72, 07.72

4. None of these

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 $r_X^{-}=\frac{C}{Zeff\left(X^{-}\right)}$

In $\text{NaF}$ crystal, $r_{Na}^{+}+r_F^{-}=230$ pm therefore, the radius of $F^{-}$ is

1. 136 pm
2. 94.5 pm
3. 112 pm
4. 115 pm

Q.

Atomic radic of fluorine and neon in $\mathring{A}$ units are respectively given by

1. 0.72, 160

2. 1.60 , 1.60

3. 0.72, 07.72

4. None of these