1.   This occurs in the upper atmosphere when neutrons produced by cosmic rays interact with nitrogen atoms.

2.   A nitro group is a molecular fragment consisting of a nitrogen atom bonded to two oxygen atoms.

3.   In its everyday gaseous form, nitrogen atoms bond in pairs.

4.   In their outermost shells, nitrogen atoms have three electrons each that are available to form chemical bonds with other atoms.

5.   The extra pressure was needed because chemical bonds between nitrogen atoms are difficult to break.

6.   The new compound is a positively charged ion, or molecular fragment, consisting of five nitrogen atoms chemically bonded to each other in a V pattern.

7.   When two nitrogen atoms are put together, their outer electrons form three separate chemical bonds between the two atoms.