The VSEPR view of the shapes of molecules is well established; molecules adopt the shape that minimises the repulsion between electron pairs, both bonding and non-bonding. Molecules can also be pictured as overlapping atomic orbitals, the 'charge-cloud' representation. This representation can be extended to reactions. It would be extremely tedious to show reactions via the charge clouds all the time, but it is instructive to see how it can be done, since then you will have a better picture of what happens during a reaction and a better understanding of what the curly arrows mean when shown in mechanisms.
There are two pages on this topic, one showing molecules and the other showing reactions.
Orbital pictures of molecules. Orbital pictures of reactions.
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