Here's why:

* Compound: A compound is formed when two or more different elements chemically combine in a fixed ratio. The resulting substance has properties distinct from its constituent elements. For example, water (H₂O) is a compound formed from hydrogen and oxygen, and its properties are different from either hydrogen or oxygen alone.

* Mixture: A mixture is a combination of two or more substances where each substance retains its own individual properties. The components of a mixture can be separated by physical means. For example, salt and pepper mixed together form a mixture. You can easily separate them using a sieve.

Key difference: The defining characteristic of a compound is that it involves a chemical reaction where the elements bond to form a new substance with a new chemical formula. In a mixture, no new substance is formed, and the components retain their individual identities.