hybrid04

Yeah -no2 groups strong deactivate aromatic rings, which would make the further subsitutions increasingly more difficult. nearly impossible to tri substitute that way. Would take some other techniques to do so

Generally ionic bonds are formed on the extremes of the periodic table. Metals and halides for example usually form ionic bonds with eachother while stuff in the middle forms covalent. Atoms like carbon with 4 valence e- tend to share.

If you are good with linear algebra and matricies you can try this link http://www.math.uiuc.edu/~djgibson/225/225_5.pdf Really it is just a process over time you get the feel for it. Complex and connected elements balance first then the smallest compounds last. Using fractions is ok if you have to then in the end you can just multiply if you have a teacher who does like fractions (i had a couple of those).