Please tell me 
How bond angle vary in NH3 , PH3 AsH3 AND SbH3 and also tell me variation of bond angle in PF3 ,
PCl3 , PBr3 AND PI3.

Asked by Virender Rawat | 18th Sep, 2014, 01:08: PM

Expert Answer:

Dear sr.virender@gmail.com

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Answer to your first question is given below:

The angle around the central atom H-M-H decreases from NH3 to SbH3 as,

Hydride

NH3

PH3

AsH3

SbH3

H-M-H angle

1070

920

910

900

 

  • This variation in bond angle can be explained on the basis of electronegativity of the central atom.
  • Since nitrogen atom is highly electronegative. So in NH3 there is high electron density around the N atom which causes greater repulsions between the electron pairs around the N atom resulting in maximum bond angle.
  • Since electronegativity decreases down the group, the electron density also decreases and consequently the repulsive interactions between the electron pairs also decrease thereby decreasing the bond angle H-M-H.

 

 
 
Regards

Topperlearning Team.

Answered by Vaibhav Chavan | 22nd Sep, 2014, 01:22: PM