What is the chemical formula for the binary compound nitrogen dioxide?

NO2

The compound, nitrogen(IV) oxide, is a radical species as written (it has 17 valence electrons), and participates in the following equilibrium:

2NO2(g)⇌N2O4(g)

The dimer is colourless, and contains a N−N bond presumed to derive from the coupling of the lone electrons on the 2 nitrogen centres; the radical species red brown.

Note that the attempt to represent the Lewis structures of these species invariably involves charge separation and FORMAL positive and negative charges on, respectively, nitrogen and oxygen. This is 1st year/2nd year inorganic chemistry rather than A level.

atomic mass = 39

number of neutrons = 20

number of protons= 19

electronic configuration = 1s2 2s2 2p6 3s2 3p6 4s1

the number of electron in first shell = 2

number of electrons in n=3 shell = 8

i think its 100.

hope this !