The carbon atoms in the CH3CHCH2 molecule are all sp2 hybridized. This means that each carbon atom has three sp2 hybrid orbitals and one p orbital. The sp2 hybrid orbitals are formed by the mixing of one s orbital and two p orbitals. The p orbital is perpendicular to the plane of the sp2 hybrid orbitals.

The sp2 hybrid orbitals of the carbon atoms in the CH3CHCH2 molecule are used to form sigma bonds with the hydrogen atoms and the other carbon atoms. The p orbitals of the carbon atoms are used to form pi bonds with each other.

The sp2 hybridization of the carbon atoms in the CH3CHCH2 molecule results in a trigonal planar molecular geometry. This means that the three carbon atoms and the three hydrogen atoms that are bonded to each carbon atom lie in a plane.