Why boiling point of CCl4 is grater than that of SiCl4 ?

The thermal stability of halides of group 14 elements is decreases in group and the trend is :

CX4>SiX4 >GeX4 >SnX4>PbX4. 

 

 The boiling point of CCl4 is grater than SiCl4   the electronic configuration of   

Carbon and silicon is 

C(6)→1s2  2s2  2p2 

Si(14)→ 1s2   2s2   2p6   3s2   3p2 

 Here we can see that  the ultimate shell  of carbon is 2 and the ultimate shell in silicon is  3. 

 

Therefor the size of carbon is smaller than Silicon. 

As the size is smaller in carbon  the  attraction of electrons to the nucleous of carbon is higher  and face no shielding effect.  

On the other hand in silicon last electrons enter into 3p orbital which feels a slight shielding effect and  the  bonding partner of thes element is "Cl"   which also has a greater size than silicon and carbon.  

 When it is attached to carbon and silicon,  carbon can attract chlorins electron as well its won electron 

 But silicon is  not such as much in carbon. 

 As a result more  energy required to boil CCl4  to SiCl4 though the polarity is greater in SiCl4.  And the electronegativity difference is higher in Si-Cl bond than C-Cl bond 

 This is the perfect ans for this question  in many website they answered wrong.