Question

Repeat Exercises 17 and 18. This time uses the values of the electronegativities of the elements given in Fig. 13.3. Are there any differences among your answers?

Short answer

Answer:

Exercise 17

(a)O is the most polar

(b) Cl is the most polar

(C)Si is the most polar

(d) S is the most polar

(e)Na is the most polar

Exercise 18

(a)Si-F is most polar

(b) P-F is more polar

(c) Ti-F is most polar

(d) Sn-H is most polar

(e) Al-Br is most polar

There is a great difference between the and 18 and 19 after calculating through the values of electronegativities given in table 13.3.

Step-by-step solution

Calculate the difference between the ∆EN of elements .

Exercise 17

(a)C, N, O

The ∆EN of $C\mathit{}is\mathit{}\mathit{2}\mathit{.}\mathit{50}eV\mathit{,}\mathit{}N\mathit{}is\mathit{}\mathit{3}\mathit{.}\mathit{0}eV\mathit{,}\mathit{}and\mathit{}O\mathit{}is\mathit{}\mathit{3}\mathit{.}\mathit{5}eV$ respectively. We can clearly see O is more polar.

(b)S,Se,Cl

The ∆EN of $S\mathit{}is\mathit{}\mathit{2}\mathit{.}\mathit{5}eV\mathit{,}\mathit{}Se\mathit{}is\mathit{}\mathit{1}\mathit{.}\mathit{92}\mathit{.}\mathit{4}eV\mathit{}and\mathit{}Cl\mathit{}is\mathit{}\mathit{3}eV$ respectively. Cl is more polar.

(c)Si, Ge, Sn

The ∆EN of $Si\mathit{}is\mathit{}\mathit{1}\mathit{.}\mathit{8}eV\mathit{,}\mathit{}Ge\mathit{}is\mathit{}\mathit{1}\mathit{.}\mathit{8}eV\mathit{}and\mathit{}Sn\mathit{}is\mathit{}\mathit{1}\mathit{.}\mathit{8}eV$ respectively. ∆EN is the same for all the elements. Considering the trend that ∆EN decreases down the group. Therefore, Si is the most polar.

(d)Tl, S, Ge

The ∆EN of $Ti\mathit{}is\mathit{}\mathit{1}\mathit{.}\mathit{8}eV\mathit{,}\mathit{}S\mathit{}is\mathit{}\mathit{2}\mathit{.}\mathit{5}eV\mathit{}and\mathit{}Ge\mathit{}is\mathit{}\mathit{1}\mathit{.}\mathit{8}eV$ respectively. The most polar is S.

(e)Na, K, Rb

The ∆EN of $Na\mathit{}is\mathit{}\mathit{0}\mathit{.}\mathit{9}eV\mathit{,}\mathit{}K\mathit{}is\mathit{}\mathit{0}\mathit{.}\mathit{8}eV\mathit{}and\mathit{}Rb\mathit{}is\mathit{}\mathit{0}\mathit{.}\mathit{8}eV$respectively. The most polar is Na.

The compound with the higher difference is more polar.

Exercise 18

(a) C-F,Si-F,Ge-F

The differences between ∆EN of $C-F$is

$\mathit{∆}EN\mathit{=}\mathit{4}eV\mathit{-}\mathit{2}\mathit{.}\mathit{55}eV\mathit{=}\mathit{1}\mathit{.}\mathit{43}eV$

The differences between ∆EN of $Si\mathit{}\mathit{-}F\mathit{}$is

$\mathit{∆}EN\mathit{=}\mathit{4}eV\mathit{-}\mathit{1}\mathit{.}\mathit{8}eV\mathit{=}\mathit{2}\mathit{.}\mathit{2}eV$

The differences between ∆EN of $Ge\mathit{-}F$is

$\mathit{∆}EN\mathit{=}\mathit{4}\mathit{.}\mathit{0}eV\mathit{-}\mathit{1}\mathit{.}\mathit{8}eV\mathit{=}\mathit{2}\mathit{.}\mathit{2}eV$

The difference between ∆EN of C-F, Si-F, and Ge-F is 1.45,2.2,2.2 respectively. Two compounds have the same difference. Therefore, Si-F is more polar because in group ∆EN decreases down the group.

(b) P-F, S-F

The differences between ∆EN of P-F is

$\mathit{∆}EN\mathit{=}\mathit{4}\mathit{.}\mathit{0}eV\mathit{-}\mathit{2}\mathit{.}\mathit{2}eV\mathit{=}\mathit{1}\mathit{.}\mathit{8}eV$

The differences between ∆EN of S-F is

$\mathit{∆}EN\mathit{=}\mathit{4}\mathit{.}\mathit{0}eV\mathit{-}\mathit{2}\mathit{.}\mathit{6}eV\mathit{=}\mathit{1}\mathit{.}\mathit{4}eV$

The difference between ∆EN of P-F, and S-F is 1.8,1.4 respectively. P-F is more polar.

(c)Ti-F,Si-Cl,Ge-Cl

The differences between ∆EN of Ti-F is

$\mathit{∆}EN\mathit{=}\mathit{4}\mathit{.}\mathit{0}eV\mathit{-}\mathit{2}\mathit{.}\mathit{1}eV\mathit{=}\mathit{1}\mathit{.}\mathit{9}eV$

The differences between ∆EN of Si-Cl is

$\mathit{∆}EN\mathit{=}\mathit{3}\mathit{.}\mathit{2}eV\mathit{-}\mathit{1}\mathit{.}\mathit{9}eV\mathit{=}\mathit{1}\mathit{.}\mathit{3}eV$

The differences between ∆EN of Ge-Cl is

$\mathit{∆}EN\mathit{=}\mathit{3}\mathit{.}\mathit{2}eV\mathit{-}\mathit{2}\mathit{.}\mathit{1}eV\mathit{=}\mathit{1}\mathit{.}\mathit{1}eV$

The differences between ∆EN are 1.9,1.3,1.1 respectively. Ti-F is the most polar.

(d)C-H, Si-H, Sn-H

The differences between ∆EN of C-H is

$\mathit{∆}EN\mathit{=}\mathit{2}\mathit{.}\mathit{55}eV\mathit{-}\mathit{2}\mathit{.}\mathit{2}eV\mathit{=}\mathit{0}\mathit{.}\mathit{35}eV$

The differences between ∆EN of Si-H is

$\mathit{∆}EN\mathit{=}\mathit{2}\mathit{.}\mathit{2}eV\mathit{-}\mathit{1}\mathit{.}\mathit{9}eV\mathit{=}\mathit{0}\mathit{.}\mathit{3}eV$

The differences between ∆EN of Sn-H is

$\mathit{∆}EN\mathit{=}\mathit{2}\mathit{.}\mathit{2}eV\mathit{-}\mathit{2}\mathit{.}\mathit{04}eV\mathit{=}\mathit{0}\mathit{.}\mathit{16}eV$

The differences between ∆EN are 0.35, 0.3, and 0.16 respectively. The most polar is C-H.

(e)Al-Br, Ga-Br, In-Br, Tl-Br

The differences between ∆EN of Al-Br is

$\mathit{∆}EN\mathit{=}\mathit{1}\mathit{.}\mathit{61}eV\mathit{-}\mathit{2}\mathit{.}\mathit{96}eV$

The differences between ∆EN of Ga-Br is

$\mathit{∆}EN\mathit{=}\mathit{2}\mathit{.}\mathit{9}eV\mathit{-}\mathit{1}\mathit{.}\mathit{81}eV\mathit{=}\mathit{1}\mathit{.}\mathit{15}eV$

The differences between ∆EN of In-Br is

$\mathit{∆}EN\mathit{=}\mathit{2}\mathit{.}\mathit{9}eV\mathit{-}\mathit{1}\mathit{.}\mathit{78}eV\mathit{=}\mathit{1}\mathit{.}\mathit{18}eV$

The differences between ∆EN of Tl-Br is

$\mathit{∆}EN\mathit{=}\mathit{2}\mathit{.}\mathit{9}eV\mathit{-}\mathit{1}\mathit{.}\mathit{62}eV\mathit{=}\mathit{1}\mathit{.}\mathit{33}eV$

The differences between ∆EN are 1.34,1.15,1.18,1.33 respectively. The most polar is Al-Br.