Nitrogen is used to protect steel from water because nitrogen has

Answer is: low reactivity.

Nitrogen (N) is in group 15 of Periodic table of elements and his atomic number is seven, which means that nitrogen has seven electrons and electron configuration: ₇N 1s²2s²2p³.

Nitrogen is inert (low reactivity) nonmetal and has five valence electrons. Nitrogen has oxidation numbers from -3 to +5.

Nitrogen molecule (N₂) has strong nonpolar triple covalent bond, that is why it is very stable and have low reactivity.