What is the difference between oxygen and oxide?

Hint:The difference between oxygen and oxide lies in their fundamental definition itself. Oxygen atom represented as O, oxygen molecule as ${{O}_{2}}$ and oxide as ${{O}^{2-}}$.

Complete step-by-step answer:Before going into the solution of discussing the difference between oxygen and oxide first we should understand what does an atom and ion means.
From the lower class we are familiar with the definition of atom that, an atom is the simplest unit or the basic entity of an element and these atoms arrange in different order in space to generate the structure of the compound. An atom will have its basic constituents like electrons, neutrons and protons and these will give us the atomic mass and atomic number of an atom. The number of protons count or the number of electrons count will be equal to that of the atomic number of an element. And the summation of the count of protons and neutrons will give the atomic mass.
These atoms are the species that take part in the chemical combination. These atoms combine with each other to form molecules.
An ion is a charged species which is formed by the losing or gain of electrons from an atom. In an atom the number of electrons and protons will not be the same. If the species is having a positive charge then they will have greater number of protons than the electrons and the charged species is called cation. And if the ion is negatively charged then the number of electrons will be greater in number than the protons and is called an anion.
So from the definition of atoms and ions we are very clear that oxygen is an atom whereas oxide is an ion which has a charge of -2, which means it has gained two extra electrons. We could also explain as oxide is the chemical compound which will have at least one oxygen atom present in them.
These oxide ions combine with other metals to form the chemical compounds whereas the oxygen will covalently bond with other atoms to form oxygen molecules.

Note:Atoms may or may not exist independently in a solution whereas the ions can exist independently in a solution. Oxygen is a very highly reactive non-metal and it readily combines with other elements to form oxide. If no other element is available for oxygen atom to bond with it bonds with another O to form the molecules.