3. When drawing Lewis structures, is it ever allowed for an atom in the second row
of the periodic table to have more than an octet of valence electrons surrounding
it?

Yes it would be a physical change.

Is there a picture or answer choices?

In any atom of any element, you will find protons and neutrons in the nucleus of any atom 

Answer:             1.0  × 10⁻⁵ msolution:                     as we know ph is given as,                                    ph  = -log [h⁺]and,                                    [h⁺]  =  10^-ph    (1)putting value of ph in eq. 1,                                    [h⁺]  =  10⁻⁵                                    [h⁺]  =  1.0  × 10⁻⁵ m