Why is lead(II) nitrate: “Pb(NO3)2” and not “Pb3NO2”? Just a bit confused because it looks a bit funny compared to how I learned how to write compounds.

Explanation:

this is because the combining capacity, ie valency, of Pb is 2 of which NO3 is 1. So, when they will combine by cross method, the compound become Pb(NO3)2 (lead II nitrate).

hope this helps you.

a. energy is absorbed in the reaction.

if in a given reaction the energy of products is greater than the energy of reactants it means that reaction is endothermic and during the reaction, the energy is absorbed by reactants. in an endothermic reaction, the products have more stored chemical energy than the reactants. and in this reaction the reactants are more stable than products before the compounds with less energy are always more stable.