"You are students and we are not students."
Translation:Ви студенти, а ми не студенти.
"Ви студенти, а ми - ні." is totally correct, if that's what you meant. "а ми ні студенти." - definitely wrong.
"Ви студенти, а ми ні" = "You are students and we are not"
So, yes, it does have the same meaning but does not possess the same grammatical structure.
I would like to know the difference in «i» «ta» and «a» because it is always used as «and» thank you