Question

what is difference between molecule of elements ana compounds

Answer 1

When two or more reactants combine to form a single product is known as combination reaction

Answer 2

ELEMENT:
elements are pure substances. they are the basic form of matter that cannot be broken down into simpler substances... this means that they contain one type of particle
eg : like in iron as a pure substance you will only find iron(fe) particles , you will not find any other particles like of copper(Cu) etc...so this iron will be called an element.

COMPOUND:
Compound is also called a pure substance. it is a substance composed of two or more elements, chemically combined with one another in fixed proportion...this means that two elements chemically combined (combined with a chemical bond) are together called compounds
eg : like in water (H2O)as a pure substance, two elements hydrogen and oxygen are chemically combined in fixed proportion (1:8) with a chemical bond...so water will be called a pure substance if it contains only H2O particles not any other particle