"The first name is not bad."
Translation:Der Vorname ist nicht schlecht.
"Nicht" comes before predicate adjectives, like "schlecht" in the above sentence.
Also, in general, "nicht" precedes whatever word(s) it is negating.
"Der Vorname" is nominative. "DEN Vornamen" is accusative. "Die Vornamen" is also plural. To my (admittedly limited) knowledge "Der Vornamen" isn't ever used.
just a few sentence back, vorname was written with an extra 'e' at the end. Why not here?
would "Der erste Name ist nicht schlecht." have been accepted
I could be wrong about this, but using erste Name would be used to signify a specific name, like a name in a list. Example: people are looking at a list of child names and someone states that the first name on the list is not bad. Vorname is the term used to signify the actual first name of a person. Maybe erste Name would make sense in context to a German person, but I'm sure technically they are two different terms and would seem that only Vorname would be used when asking the first name of a person.
I would use 'Forename' in English for 'Vorname'. I agree that this could as likely had been este Name.
Kein comes before a noun to negate it, as in "Der Mann isst kein Apfel". Schlecht is an adjective.
'kein' = 'not a' -- the word is k + ein, and you use it in place of "ein" (or keine/eine for feminine).
Using kein there would be like saying "The first name is not a bad", which doesn't make sense.