How do molecules of elements and molecules of compounds differ? in what ways are they similar?

Explanation:

Difference between the two:

Molecules of elements are defined as the substances which are made up of similar type of atoms. For Example: etc..

Molecules of compounds are defined as the substances which are made up of different type of atoms. For Example: etc..

Similarity between the two:

These two substances are known as pure substances. 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. Compounds and elements are considered as pure substances.