Why are vitamins named the way they are? (A, B, C, D, E and so on)

They are just the abbreviated full names: Vitamin Alfredo, Vitamin Beef, Vitamin Cheese, Vitamin Deez Nuts, and Vitamin Egg

They were just alphabetical, A was the first one they found, B the second, etc.

Except, K was named "Koagulation" from the fact it helps blood coagulate

And also, the "B vitamins" were originally one extract, a serum used to treat a disease caused by B vitamin deficiency. Later, we learned that serum actually had several different molecules in it, now seperated as B2, B6, etc.

They were labeled alphabetically based on when they were discovered. Also, Vitamin D's label was a misnomer as it's converted into a vital hormone needed for the body to properly function.

When they were naming vitamins they must have thought there were going to be way more vitamins than there ended up being. OK let's name these: Vitamin A, Vitamin B... Ok, man, slow down, we've got a lot to cover here. B2, B3, B4, B5, B6, B12. Then they got to E and they were like 'We're pretty much done. We've got all those damn B's. This is embarrassing. Let's just skip to K and get the hell out of here.

There’s no vitamin F.