Yeah, and when Ukrainian are very fasting they are swallowing both soup and plate :))
In first, українці (small letter on the beginning and "і" on the end). In second, when we speak seriously in usual and normal situation we always say "eat soup" and "eat borshch" and never "drink" even if we were drinking it really. But if you want to make a joke you might say "drink soup", because it sounds really wild and you are risking to be misunderstandable.
I know that the word українці, is not a name or something like that and also plural form of noun has ending -i, noun declension. I did mistake, sorry.
However, in my language, name of people of the same nationality are upper cased, so as I am Slovak, I would write it like this: Українці.
If на = on - locative (на столі - on the table). If на = at (на вечірці - at the party, на концерті - at the concert), it also takes locative
If it's a sentence like this one where you translate на as "for", it takes accusative.