10. How many elements do all the "d" orbital span (go across) in each period? (circle your answer) a) 2
b) 6
c) 10
d) 14

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.