Search the Internet for the definition of states of matter and much comes up. Perhaps you are the sort of reader who peeks first at Wikipedia to get some ideas what other sites you will visit to obtain answers to your questions. At any rate, you will note basic descriptions for the states of matter you experience every day.
Take the following discussion for what it is: a hypothetical discussion on the nature of matter. If you can demonstrate its veracity or illegitimacy, please do that in the Comments section, below.
States of Matter
Solid: “Atoms or molecules fixed in location and locked in place.” How are these particles locked into place? They bond to each other and do not readily move around, much like the assembled pieces in a three dimensional puzzle.
Liquid: Wikipedia says a liquid is: “matter [that] maintains a fixed volume, but has a variable shape that adapts to fit its container. Its particles are still close together but move freely.” It takes energy to move about, so a liquid possesses more energy than its corresponding solid.
Gas: Matter in the gaseous state has variable volume and shape to fit its container. Its particles are not close together or fixed in place. Gases possess still more energy than a liquid does. One might argue that a lone particle isolated constitutes a low-pressure gas, but consider: what about a grain of salt? And if that grain is reduced in size and reduced in size and reduced in size, is it suddenly a gas when you get down to one molecule?
The Simple Conclusion
Notice that for all matter, the motion of particles relative to one another, as well as their container fit define whether the collection is solid, liquid, or gas. But an individual particle has no other particle to which it binds or does not bind. Neither does it fill a container shape. While a particle’s energy can suggest which state a collection of particles is probably in, statistically, it cannot absolutely do so. A discussion of states of matter for lone particles would seem to be a fruitless discussion.
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