The radius of a copper atom is 128 pm. how many copper atoms would have to be laid side by side to span a distance of 4.65 mm?

The distance covered by each atom of copper will be twice the radius of each atom, which is its diameter

it will be like as shown in diagram....

Let the number of atoms required is "n"

thus total atoms required will be

Let us convert pm to mm for unit cancellation.

Thus

hence

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.