As the electronegativity of central atom decreases, the repulsions between element hydrogen bond pairs decreases and hence, the angle decreases accordingly. Thus, H2O has largest bond angle (104.5∘). Hence, order of bond angle is
H2O>H2S>H2Se>H2Te Bond angle 104.5∘‌‌∴97.1∘‌‌97.0∘‌‌90∘