How do you draw the lewis structure for NO2?

Five from nitrogen, and 12 from the oxygen atoms...and so we got 8 and a HALF electron pairs to distribute...17 electrons in total

As is typical, the least electronegative atom is placed in the middle to give...

#O=stackrel(dot)N^(+)-O^(-)#

From left to right as we face the page, each atom is associated with SIX, FOUR, and SEVEN valence electrons, giving rise to formal charges of #0#, #+1#, and #-1#. Of course, we could write the other resonance structure...

#""^(-)O-stackrel(dot)N^(+)=O#

And so #NO_2# is a NEUTRAL, BENT molecule...whose geometry is based on a trigonal plane...#/_O-N-O=120^@# to a first approx., but #115^@# in actuality....

Why don't you try it for nitrite ion, #NO_2^(-)#...how does the Lewis structure evolve..?

And just to add, that the formal Lewis structure of #NO_2# is useful when we assess reactivity... #NO_2# can READILY dimerize (alternatively #N_2O_4# can readily undergo dissociation.

#(""^(-)O)O=stackrel(+dot)N + stackrel(+dot)N=O(O^(-)) rarr underbrace(""^(-)(O)O=stackrel(+dot)N-stackrel(+dot)N=O(O^(-)))#

#N_2O_4-="dinitrogen tetroxide"#

The nitrogen atom in #NO_2# or #N_2O_4# is said to be quaternized, i.e. it bears a formal POSITIVE charge....