Chemistry · Fundamental Principles of Organic Chemistry

Cyclopropane has carbons with four bonds, hence they are SP³, but with bond distances less than normal alkanes and C-C-C bond angles of 60 degrees and H-C-H angles of 120 degrees. They are a special case as usually SP³ hybridization displays 109.5-degree angles

In a tetrahedral molecular geometry, a central atom is located at the center with four substituents that are located at the corners of a tetrahedron. The bond angles are cos−1(−1⁄3) = 109.4712206... ° ≈ 109.5° when all four substituents are the same, as in methane (CH 4) as well as its heavier analogs. Methane has a 109.5-degree bond angle and is tetrahedral 

Cyclopropane has carbons with four bonds, hence they are SP3, but with bond distances less than normal alkanes and C-C-C bond angles of 60 degrees and H-C-H angles of 120 degrees. They are a special case as usually SP3 hybridization displays 109.5-degree angles.

Mixing and reacting 1s and 2p orbital of the same atom of nearly the same energies to form three new sp2 hybrid orbitals with equal energies, maximum symmetry, and definite orientation in space is called sp2 hybridization. For example, the formation of an ethylene molecule. It has a 120-degree bond angle 

The NH3 bond angle is 107 degrees because the hydrogen atoms are repelled by the lone pair of electrons on the Nitrogen atom. The central atom in ammonia (NH3), which is nitrogen, is the one that undergoes hybridization to give sp3 hybridized molecules.