You're right to think that sp² hybridized carbon is more electronegative than sp³ hybridized carbon. Here's why:

* Hybridization and Electron Density:

* sp³ hybridized carbon has 25% s-character and 75% p-character. The s orbital is smaller and closer to the nucleus than the p orbitals, meaning the electrons in the s orbital are held more tightly.

* sp² hybridized carbon has 33% s-character and 67% p-character. The higher s-character means a greater proportion of the electron density is closer to the nucleus.

* Electronegativity: Electronegativity is a measure of an atom's tendency to attract electrons towards itself in a chemical bond. Since the electrons in sp² hybridized carbon are held more tightly (due to the higher s-character), the carbon atom is more electronegative.

In summary: The higher s-character in sp² hybridized carbon leads to greater electron density closer to the nucleus, making it more attractive to electrons and therefore more electronegative.