Lithium has two stable isotopes, lithium-6 and lithium-7. The atomic number of lithium is 3. Explain how the two are the same and how they are different.

Explanation:

The two isotopes of lithium given are similar in the sense that they have the same atomic number which is 3.

Every kind of an atom of an element have the same atomic number. Atomic number is the number of protons in an atom.

The atoms are different in that they have different mass number because the number of protons they contain are different.

So for isotopes;

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.