How many neutrons does an atom of al-27 have? (hint: look at the periodic table for the atomic number aluminum (al) 13 14 27 40 aluminum has the atomic number of 13?

Yeah!! Atomic number of Aluminum  is 13

No. of neutrons = Mass number - atomic number

 27 - 13 =14

So, the number of neutrons in Al-17 is 14

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.