What is sp3 hybridization characterized by?

sp3 hybridization is characterized by one 2s orbital mixing with three 2p orbitals to form four equivalent sp3 hybrid orbitals. This process involves the promotion of one of the 2s electrons to a 2p orbital, leading to the formation of the four sp3 hybrid orbitals. Each of these hybrid orbitals has the same energy level and can form sigma bonds with other atoms or hold lone pairs.

The correct answer reflects this essential aspect of sp3 hybridization, highlighting the promotion of an electron, which is crucial for forming tetrahedral geometries with bond angles of approximately 109.5 degrees, rather than the 120 degrees indicated in one of the other choices, which aligns with sp2 hybridization. Additionally, while it might be true that four orbitals are hybridized for bonding, it does not capture the specific process of electron promotion which is a key feature of the sp3 hybridization. Therefore, the promotion of an electron to enable hybridization is a defining characteristic of sp3 hybridization and provides a clear understanding of how these orbitals form.