The double bonds in alkenes and double bonds in carbonyl groups are VERY different in terms of reactivity. The C=C is less reactive due to C=O electronegativity attributed to the oxygen and its two lone pairs of electrons.  One pair of the oxygen lone pairs are located in 2s while the other pair are in 2p orbital where its axis is directed perpendicular to the direction of the pi orbitals.  The Carbonyl groups properties are directly tied to its electronic structure as well as geometric positioning.  For example, the electronegativity of oxygen also polarizes the pi bond allowing the single bonded substituent connected to become electron withdrawing.

Carbonyl Bond in Organic Chemistry

Carbonyl compounds are organic compounds that contain a carbonyl group, which is a functional group composed of a carbon atom double-bonded to an oxygen atom (C=O). The carbonyl group is one of the most important functional groups in organic chemistry, and it is found in a wide range of compounds, including aldehydes, ketones, carboxylic acids, esters, and amides. The carbonyl bond between carbon and oxygen is a polar covalent bond, which means that the electrons in the bond are not shared equally between the two atoms.

Nucleophilic and Electrophilic Centres

In organic chemistry, a nucleophile is a chemical species that has an unshared pair of electrons and is attracted to positively charged or electron-deficient atoms (electrophiles). An electrophile is a chemical species that has a partial or full positive charge and is attracted to negatively charged or electron-rich atoms (nucleophiles).

In the case of the carbonyl bond between carbon and oxygen, the carbon atom is electron-deficient and is therefore the electrophilic centre, while the oxygen atom is electron-rich and is the nucleophilic centre. This means that the oxygen atom can attack the carbon atom, forming a new bond and breaking the original carbon-oxygen bond.

Polarisation of the Carbonyl Bond

The carbonyl bond between carbon and oxygen is a polar covalent bond, meaning that the electrons in the bond are not shared equally between the two atoms. The oxygen atom is more electronegative than the carbon atom, which means that it attracts the electrons in the bond more strongly than the carbon atom. This results in a partial negative charge on the oxygen atom and a partial positive charge on the carbon atom.

The polarisation of the carbonyl bond has important implications for the reactivity of carbonyl compounds. The partial positive charge on the carbon atom makes it an electrophilic centre, which means that it can be attacked by nucleophiles. The partial negative charge on the oxygen atom makes it a nucleophilic centre, which means that it can attack electrophiles.

Conclusion

In conclusion, the carbonyl bond between carbon and oxygen is a polar covalent bond, with the carbon atom being the electrophilic centre and the oxygen atom being the nucleophilic centre. The polarisation of the bond has important implications for the reactivity of carbonyl compounds and their reactions with nucleophiles and electrophiles.