At which condition will the entropy of a pure solid be zero? a. when a substance is at absolute zero b. when a substance is undergoing a phase change c. when a substance is in its elemental form d. when the temperature is 0ºc

Option (a) is the correct answer.

Explanation:

The minimum temperature at which there is no heat energy between the molecules of a substance is known as absolute zero.

Absolute zero temperature is also known as zero Kelvin.

Whereas entropy is the measure of randomness. More is the temperature more will be the motion of particles of a substance. Hence, more will be its entropy.

Thus, we can conclude that when a substance is at absolute zero the entropy of a pure solid be zero.

explanation:

metals have excess of electrons whereas non-metals have deficiency of electrons. thus, in order to gain stability metals easily donate their electrons to the non-metals.

for example, electronic configuration of sodium is and electronic configuration of phosphorous is .

when a phosphorous atom and sodium atom combine together then sodium will donate is extra one electron to the phosphorous atom. as a result there will be formation of ionic bond between sodium and phosphorous.

the reaction will be as follows.

there, are three sodium sodium atoms and each of them will donate its one extra electron to phosphorous atom. thus, the sub-shell of phosphorous gets completely filled.  

thus, we can conclude that electrons are transferred from atoms of sodium to atoms of phosphorous. this transfer makes the sodium atoms donate one electron and the phosphorous atoms to gain one electron. as a result, the sodium and phosphorus atoms strongly attract each other.

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