Air is compressed, cooled and expanded to liquid; a fractional distillation column boils off N2 at 77 K, before O2 at 90 K.
Research Elements N · atomic number 7 Reactive nonmetal · period 2, group 15 [He] 2s2 2p3 Shells: 2, 5 Valence electrons: 5 in the outer shell (2s2 2p3) Green dots are the outer shell's s and p electrons. Softer green dots are the d electrons of transition metals, and the d and f electrons of lanthanides and actinides: they often take part in bonding, but not always. Grey dots are the core. Ground-state configuration from the NIST Atomic Spectra Database (A. Kramida, Yu. Ralchenko, J. Reader and the NIST ASD Team). Abundance is the mole fraction of the element found as that isotope on Earth; digits in parentheses are the uncertainty in the last digits. Masses and abundances from NIST, Atomic Weights and Isotopic Compositions (J. S. Coursey, D. J. Schwab, J. J. Tsai and R. A. Dragoset, National Institute of Standards and Technology).Nitrogen
Electrons
How it's obtained
Natural isotopes
Isotope Relative atomic mass Abundance How this isotope is separated 14N 14.00307400443(20) 0.99636(20) 15N 15.00010889888(64) 0.00364(20) Cascaded chemical exchange between NO gas and HNO3 solution: 15N prefers the acid phase and enriches down the column (the Nitrox process).