NITROGEN At standard temperature and pressure, nitrogen is a colorless, odorless gas. Approximately 78% of the air we breathe is nitrogen.

Physical Properties

Atomic Number: 7
Mass Number: 14.00674
Electron Configuration: 1s²2s²2p³
Melting Point: -209.86^oC
First Ionization Energy: 1402 kJ/mol
Atomic Radius: 74 pm
Ionic Radius: 171 (N₃^-)
Electronegativity: 3.0

Liquid Nitrogen. In this photo, liquid nitrogen is being poured from a dewar into a beaker. Wisps of water vapor condense from the air due to the extreme cold, and the beaker appears frosted.