* Two or more elements: It is composed of two different elements: silicon (Si) and oxygen (O).
* Fixed ratio: The elements are always present in a fixed ratio, in this case, one silicon atom for every two oxygen atoms.
* New properties: Silicon dioxide has distinct properties that are different from both silicon and oxygen individually. For example, it is a hard, transparent solid, unlike silicon which is a brittle, gray solid, and oxygen which is a colorless gas.
* Chemical bonding: Silicon and oxygen are held together by strong covalent bonds, forming a crystal lattice structure.
In contrast to mixtures, where elements or compounds are physically combined and retain their individual properties, compounds have unique properties due to the chemical bonding between their constituent elements.
Therefore, silicon dioxide meets all the criteria to be classified as a compound.
