The Standard Model of particle physics is the theory describing three of the four known fundamental forces (the electromagnetic, weak, and strong interactions, and not including the gravitational force) in the universe, as well as classifying all known elementary particles. It was developed in stages throughout the latter half of the 20th century, through the work of many scientists around the world, with the current formulation being finalized in the mid-1970s upon experimental confirmation of the existence of quarks.
The Standard Model of particle physics is the theory describing three of the four known fundamental forces in the universe, as well as classifying all known elementary particles.
So yes! A mixture can contain just elements if those elements are not chemically reactive to one another. Air is a great example of an elemental mixture as it contains nitrogen, oxygen, and argon (along with some other compounds).
