In this video, we look at four (4) aldehydes - formaldehyde, acetaldehyde, propanal, and butanal - and two (2) ketones - acetone and 2-butanone. The Mulliken partial charges on all atoms, but especially the carbonyl carbons, were performed using the Gaussian 03W suite of programs at the B3lYP/6-311+G(3df,+ 2p) level on B3LYP/6-311G optimized geometries. Direct comparison in each shows a substantial increase in the positivity of the partial charge on the carbonyl carbon, making it a stronger electrophile. This is a common technique when using weak nucleophiles; we essentially "strengthen" the nucleophile by "activating" the electrophile by protonation.
