<span>The esters need to evaporate to be smelled.</span>
Subscripts cannot be changed because they are the ratio of the amount. And as we know, in a chemical equation/reaction, mass cannot be created nor destroyed. Therefore, we cannot change subscripts, however, we could change coefficients. <span />
I think it might be Core Electrons and Valence Electrons respectively. As core electrons are the name of the electrons for the inner levels. While valence is the outer shell electrons.
