Question

ClO3َ AND ClO4 ions have same number of electrons around the centeral chlorine atom but their geometry is different . why?

Answer 1

This one lone pair of electrons exerts a big repulsive force on adjacent bond pairs to compress bond angles to make them smaller than 109.5 o and it is 107 o. But ClO 4 - ion is tetrahedral shape and has 4 bond pairs and no lone pair of electrons, and bond angle is 109.5 o.