The enthalpy change for an exothermic reaction is negative because heat is being released, so that takes out two of the responses. Since energy is being released into the surroundings due to the exothermic reaction, the potential energy of the products is lower than that of the reactants. Energy is being put in to make the reaction occur, but then that energy is all being released into the surroundings thus a lower potential energy level for the products
Answer:
the ionic radius of the anion 
Explanation:
From the diagram shown below :
The anion 
is located at the corners
The cation 
is located at the body center
The Body diagonal length = 
∴ 
Given that :
(i.e the ratio of the ionic radius of the cation to the ionic radius of
the anion )
Also ; a = 664 pm
Then :
Therefore, the ionic radius of the anion
