on basis of stereochemical rules of VSEPR theory explain bond angle of hydrides of group VI elements decrease?

Question

in order H2O > H2S > H2Se > H2Te
(104.5) (92.5) (91.0) (89.5) in inorganic chemistry
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Answer 1

All belong to the same group thus the only factor affecting the angle is the change in the electronegativity:

The lower the electronegativity the higher the repulsion between the lone pairs and thus the smaller the angle:
Think of it this way: A very electronegative atom like O will pull electrons from H towards itself more than the other elements in the O-H bonds. Thus the electron density near the space where the O-H bonds are will be closer to that of the lone pair and thus repulsion with the lone pairs in the outer shell of O is greater.