How does the complete filling of a subshell affect E? produces chemical stability; therefore increases E produces chemical stability; therefore decreases E no apparent effect E becomes very high because the atom becomes inert

produces chemical stability; therefore decreases E

Explanation:

E is generally refers to the activation energy. Activation energy is a type of energy required for the starting of chemical reaction. Atoms are reactive when their outermost shell is incomplete and only be stable when the outermost shell filled with electrons. so for the reaction when the atom is stable activation energy is required but when the atom is stable, there is no need for activation energy.

answer: enthalpy

explanation:

for a exothermic reaction, the energy is released i.e. the energy of the products is lower than the energy of the reactants.

= enthaply

= energy of products

= energy of reactants

as , thus comes out to be negative. negative value of enthalpy shows that the reaction is exothermic.