Why is the Carbon always Delta positive in mechanisms?

Specifically in A-level, In ANY case has/will the carbon ever be delta negative. If so why or why not.

There are cases in A level where carbon could assume a δ- charge in a mechanism, though iirc none of the mechanisms you are taught involve such carbons (they are either δ+, or have a formal +1 or -1 charge), but it is the unfamiliar mechanisms you could be expected to work out in an exam that may involve them.

To establish whether the carbon has a δ+ or δ- charge, you need to consider what it is bound to and if the things it is bound to are more or less electronegative than carbon. Halogens, oxygen and nitrogen are more electronegative than carbon and (most) metals are less electronegative than carbon.

So if its a carbon-oxygen/halogen/nitrogen bond the carbon would be delta negative in this scenario? In that case, how would i approach the mechanism and would it be any different?

Carbon would take a δ- charge if covalently bonded to a less electronegative species.

So for instance, if you had a:
C-B bond C δ- B δ+
C-P bond C δ- P δ+
C-S bond Non-polar
C-N bond N δ- C δ+

However as you said, at A Level, you're unlikely to encounter a molecule with a C δ- charge. There are also considerations with surrounding atoms, e.g. If a carbon atom was bonded to both Boron and Oxygen - however, you're still unlikely to encounter that scenario.

Hope this helps!

Alright, Thank you! I think it would be best for me to just ignore this as a whole and invest my concerns in other areas 😅