Postulates of Dalton’s atomic theory.

● The matter is made up of indivisible particles known as atoms.

● The properties of all the atoms of a given element are same including mass. This can also be stated as all the atoms of an element have identical mass while the atoms of different elements have different masses.

● Atoms of different elements combine in fixed ratios to form compounds.

● Atoms are neither created nor destroyed. This implies that during chemical reactions, no atoms are created nor destroyed.

● The formation of new products (compounds) results from the rearrangement of existing atoms (reactants).

● Atoms of an element are identical in mass, size and many other chemical or physical properties, but atoms of two-different elements differ in mass, size and many other chemical or physical properties.

Hence, the correct option is D.