Hybridization.....sp3 and sigma bonds

hoay SG

Are sp3 hybridized atoms only have sigma bonds...such as in CH4, NH3.

and sp2-hybridized atoms may have sigma bond as well as pi-bonds....such as BF3.

How we know that an atom has which type of hybridization??

UltimaOnline SG

The correct way of determining orbital hybridization, is by looking at the electron geometry (and has nothing to do with sigma vs pi, single vs double vs triple bonds, as is often erroneously taught in schools).

For instance, the N atom is NH3 has 1 lone pair and 3 bond pairs, hence electron geometry is tetrahedral, while molecular geometry is trigonal pyramidal.

In determining orbital hybridization, we focus on the electron geometry.

Since the electron geometry about the N atom in NH3 is tetrahedral, the orbital hybridization is sp3.

sp = s + p = 2 electron charge clouds = linear.

sp2 = s + p + p = 3 electron charge clouds = trigonal planar.

sp3 = s + p + p + p = 4 electron charge clouds = tetrahedral.

sp3d = s + p + p + p + d = 5 electron charge clouds = trigonal bipyramidal.

sp3d2 = s + p + p + p + d + d = 6 electron charge clouds = octahedral.