How does an atom differ from a molecule? in what ways are they similar?

Explanation:

Difference between the two:

Atoms are defined as the smallest particle of a chemical element that exists. They are made up of protons, electrons and neutrons. Elements have similar kind of atoms present in them while compounds have different type of elements present in them.

Molecules are formed when two or more atoms of similar or different kinds bond together. For Example: etc...

Similarity between the two:

A pure substance is defined as the substance which is formed by same or different type of atoms which are chemically combined in a fixed ratio by mass. Atoms and molecules are considered as pure substances.

definition

                    entropy is a measure of the randomness or the extent of disorder of a chemical process.

                      enthalpy is a measure of the heat change of a reaction occurring at a constant pressure.

measurement units:

                        entropy is measured in joule per kelvin (jk⁻¹)   whereas enthalpy is measured in joule per mole (jmol⁻¹)

requirements:

                            entropy has no requirements or limits, and its change is measured by the division between the heat change of the chemical process and the temperature.

                              in contrast, enthalpy can only be related to the heat change of the reaction under standard conditions.