1. Carbon's ability to form four covalent bonds: Carbon has four valence electrons, meaning it can form four covalent bonds with other atoms. This allows carbon to create long chains, branched structures, and rings, forming the backbone of complex molecules.
2. Carbon's ability to form stable bonds with itself: Carbon can readily bond with other carbon atoms to form long chains and rings. This property, known as catenation, is unique to carbon and contributes greatly to the vast array of organic molecules.
These two properties, combined with the fact that carbon can also bond with a wide variety of other elements like hydrogen, oxygen, nitrogen, and sulfur, allows for the creation of millions of different organic compounds.
