How can you determine the number of shells in an atom of a certain element, based on the element's position on the periodic table?

 At some point in your chemistry education, you may have been introduced to the song “The Elements in which Tom Lehrer does a rapid

fire musical rendition of all the elements' names. Like me, you may even have been offered the opportunity to memorize this song for extra credit. If so, it’s possible that you still remember the names of all the elements, which is an impressive feat—not to mention a fun trick to pull out at parties.

Explanation:

pie chart because it is in percents ( % )

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.