Ya this is based on repultion of electron pair so l.p-l.p repultion is maximum while bond pair bondpair electron repultion is minimum because it is more localised.as the l.p -l.p repulstion increases bond angle decreases while as the bond pair bond pair repultion increses bond angle increses.electron pair arrange in such a way that they get minimum repultion and high stability.for example ClF3 molecule is T shape molecule because all lone pair are down and up side of table while three chlorine atoms are arrange in T shape so that minimum repulstion occurs.by this we decide the shape of different molecules like SF4 contains one lone pair so that shape is seasaw type .like XeOF4 and BrF5 both have 5 sigma bonds and one lone pair so both have same geometry squre pyramidal with sp3d2 hybridisation.
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lone pairs
