Construction Question

sure, just don't stand under it

Maybe, but why would you want to do that?

You have not given enough information for us to provide a satisfactory answer.

Provide photographs, plans, and how slab, column, and beam reinforced + verifiable concrete concrete compressive strengths (via NDT).

If you cannot do so, than I suggest that you hire a qualified & licensed Structural Engineer from your region/locale.

assuming you mean the first floor above the ground floor, the answer would be yes and no.

Building a new floor with only one column and one beam would give you either a very small floor or a very well balanced floor which you would have to be very careful about the weight distribution on but it is possible.

not sure what you mean, it doesn't sound very stable, usually columns run from the bottom to the top of the building