How do you find the lone pairs in a molecule? - Answers

FIRST OF all use the following formula for finding out the hybridisingby H= S+(1/2)[E - V +/- C]HERE H is the hybridisationS is the no of surrounding atoms to the central atomE is the no of outer shell es in the central atomV is the no of valence electrones of the central atomand C is the charge on the moleculeC= +ve for -ve charge and -ve for the + ve charge.if H= 2,3,4,5,6,7 then the hybridization will be sp sp2 sp3 sp3d sp3d2 and sp3d3 respectively and ifsp the structure is linearsp2 then trigonal planerv shape for the one lone pairsp3 then tetrahedralpyramidal (1lone pair)v shape (2lone pair)and linear (3lone pair)sp3d trigonal bipyramidaldistorted bipyramidal (1 lone pair)t shape (2 lone pair)linear (3 lone pair)sp3d2 octahedralsquare planer(1 lone pair)planer (2 lone pair)sp3d3 pentagonal bipyramidaldistorted pentagonal bipyramidal (1 lone pair)thus after knowing the hybridization we can get the structure closer to some. now for knowing the no of lone pairs we follows following pathexample we take NH3HERE WE find first the hybridisationby the above mentioned formulahere central atom is N and S= 3 atomsand E= 5 (outer shell es) and C=0 and V= 3 thusH= 3 + 1/2*[ 5-3+0]= 3+1=4 means sp3 hybridization.nowfind out the no of lone pairwe know the no of outer es =5use of es by H atom = 3 then remaining atoms= 5-3=2/2=1 lone pairso the structure is pyramidal.SOLVED BYDEVENDRA KUMAR VERMA(RESEARCH SCHOLAR),DELHI TECHNOLOGICAL UNIVERSITY, DELHI.