The chemical reaction na+ + cl- nacl is best described as a(n)

Ionic bond because transfer of electrons is taking place

A combination reaction. This is because two elements combined to form one compound.
Hope this helped. 

The air is going to come out because of the low pressure.

Non metal is an element or substance that is not a metal metal is a solid material that is typically hard, shiny, malleable, fusible, and ductile, with good electrical and thermal conductivitymetalloid is an element (e.g., germanium or silicon) whose properties are intermediate between those of metals and solid nonmetals. they are electrical semiconductors.