give reason why bond angle decreases from H₂O to H₂Te?

bond angle down the group decreases because as we go down the group the size of the atom increases so the lone pairs spreads more which results in decrease in distance between the bond pairs and hence the bond angle decreases.

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On moving down the group due to decrease in electronegativity, the bong pair of electrons are away from lone pair of electrons, thus chances of repulsion between lone pair and bond pair of electrons causes decrease in bond angle.
Thus down the group bond angle of hydrides of oxygen family decreases.

upon going down the group the lone pair of electrons tend to be diffused in much larger orbitals thus it gives a larger repulsion to the bond pair which ultimately reduces the bond angle.
at the top of the group usually the lone is well directed and thus repulsion is a little lesser

The reason for the decrease in bond angle is because the repulsions between the lone pair increases with size and the size increases down the group. Also, these molecules come under a special category called drago molecules and they have no hybridisation. They have minimum bond angles.

As we move down the group the size of central atom goes on increasing and electronegativity goes on decreasing. Consequently the bond pair of electron are away from the central atom as we move from H2O to H2Te. As a result of this force of repulsion between the bond pair decreases as we move from oxygen to Tellurium and hence the bond angle decreases in the same order

In H2O,H2S, H2Se, H2Te the bond Angle decreases. The reason for this is that the repulsions between lone pair increases by size and the size increases down in the group .Also the molecules have no hybridisation. Due to they comes under dragons molecules . So, they have minimum bond angles group