sh2 and oh2 which have smallest bond angle
1. H2S will have a smaller bond angle as compared to H2O.
2. There are two reasons to support this statement above :
(a) Size of the central atom: As we know that oxygen is smaller in size than sulphur,so the two bond pairs of 2 O-H bonds and two lone pairs of oxygen experience a lot of repulsion. So,According to VSEPR theory,they remain far way from each other,at larger bond angles. However,in the case of sulphur,size is much larger so the repulsion does not effect the the bond angles as lone pairs and bond pairs are de-localised over large surface area.
(b) Inert pair effect: According to this,as we move down the group ,the energy gap between s and p orbital increases and s orbital becomes reluctant to participate in hybridisation. So,in the case of sulphur,the bonding is done mostly by pure p orbitals and we know p orbitals are 90 degree to each other. Therefore,bond angle in H2S is less as compared to H2O,where hybridisation is taking place and bond angle is 108 degree(due to lone pair-bond pair repulsion,it decreases to 108 degrees from 120 degrees).
2. There are two reasons to support this statement above :
(a) Size of the central atom: As we know that oxygen is smaller in size than sulphur,so the two bond pairs of 2 O-H bonds and two lone pairs of oxygen experience a lot of repulsion. So,According to VSEPR theory,they remain far way from each other,at larger bond angles. However,in the case of sulphur,size is much larger so the repulsion does not effect the the bond angles as lone pairs and bond pairs are de-localised over large surface area.
(b) Inert pair effect: According to this,as we move down the group ,the energy gap between s and p orbital increases and s orbital becomes reluctant to participate in hybridisation. So,in the case of sulphur,the bonding is done mostly by pure p orbitals and we know p orbitals are 90 degree to each other. Therefore,bond angle in H2S is less as compared to H2O,where hybridisation is taking place and bond angle is 108 degree(due to lone pair-bond pair repulsion,it decreases to 108 degrees from 120 degrees).