Atomic & Quantum Theory

The only positive ion found in an aqueous solution
of sulfuric acid is the
(1) hydroxide ion (3) sulfite ion
(2) hydronium ion (4) sulfate ion

HNO3(aq)+LiOH(aq) ---->

NH₄NO₃ (aq) + KOH (aq) → NH₃ (g) + KNO₃ (aq) + H₂O (l)

Is this balanced already, and what type of reaction is this.  I am trying to focus on the potassium nitrate as one of the products.

oxygen, O

I'm stressing out with quantum numbers. Even the simplest ones, I'm having a difficult time finding the number of electrons each subshell can accommodate. For example, if n=2 and l=0, then how many electrons can each subshell accommodate?

H₂S + K₂Cr₂O₇ + HCl ------> S + CrCl₃ + KCl + H₂O

MnO₄ + C₂O₄^-2 + H⁺ -----> Mn₂⁺² + CO₂

I Just can't balance it, i've been trying it for a while. Maybe the question itself was wrong but I've done it and redone it and it just doesn't work. Thanks! 

Calculate the de Broglie wavelength of an average Xe atom at 27 deg Celsius. 

How do I calculate this using  de Broglie's formula?

I don't understand how to determine the four different quantum numbers if you are given a certain element from the periodic table like lithium for example.