JEE MAIN - Chemistry (2006 - No. 51)
The decreasing values of bond angles from NH3 (106o) to SbH3 (91o
) down group-15 of the periodic table is due to
increasing bp-bp repulsion
increasing p-orbital character in sp3
decreasing lp-bp repulsion
decreasing electronegativity
Explanation
Nitrogen(N) atom is smaller in size so it's lone pair is relatively unstable. That is why repulsion between lone pairs present on nitrogen atom and bonded pairs of electrons is relatively high.
But size of Sb is more so its lone pair is relatively stable. That is why it does not want to perticipate in bond pair lone pair repulsion and decreases lp-bp repulsion.
But size of Sb is more so its lone pair is relatively stable. That is why it does not want to perticipate in bond pair lone pair repulsion and decreases lp-bp repulsion.