when drawing lewis structures, is it ever allowed for an atom in the second row of the periodic table to have more than an octect of valence

no it is not allowed

Explanation:

Liwis structure shows the elements symbol with dots thet represents valance electrons ; in second row elements their atomic number is 3 up to 10 , from Li up to Ne from their electron configuration their valance electron will be from 1 up to 8 respectivelly ,if lewis structure represents the element with it is symbol and dots that represents valance electron the second row elements cannot have more than an octet of valance electrons surrounding it.

adding or remove a gaseous reactant or product changes the concentrations. if the concentration of reactant or product is increased, the system will shift away from the side in which concentration was increased (i.e. if the concentration of reactants is increased, the system will shift toward the products. if more products are added, the system will shift to form more reactants). conversely, if the concentration of reactant or product is decreased, the system will shift toward the side in which concentration was decreased (i.e. if reactants are removed, the system will shift to form more reactants. if the concentration of products is decreased, the equilibrium will shift toward the products).

explanation: