This material not only talks about how particles are located in solids, but also how they move in gases or in liquids. The types of crystal lattices in various substances will also be described.
State of aggregation
There are certain standards that indicate the presence of three typical states of aggregation, namely: solid, liquid and gas.
Define the components for each state of aggregation.
- Solids are practically stable in volume and shape. The latter change is extremely problematic without additional energy costs.
- The fluid can easily change shape, but retains volume.
- Gaseous substances retain neither shape nor volume.
The main criterion by which the state of aggregation is determined is the location of the molecules and how they move. In a gaseous substance, the minimum distance between individual molecules is much greater than themselves. In turn, the molecules of liquid substances do not disperse over long distances in their usual conditions and retain their volume. The active particles in solids are arranged in a strictly defined order, each of them, like a pendulum of a clock, moves near a certain point in the crystal lattice. This gives solids special strength and rigidity.
Therefore, in this case, the most relevant question is how the active particles are located in solids. In all other cases, atoms (molecules) do not have such an ordered structure.
Fluid features
It is necessary to pay special attention to the fact that liquids are a kind of intermediate link between the solid state of the body and its gaseous phase. So, when the temperature decreases, the liquid hardens, and when it is higher than the boiling point of a given substance, it goes into a gaseous state. However, the liquid has common features with both solid and gaseous substances. So, in 1860, the outstanding domestic scientist D.I. Mendeleev established the existence of the so-called critical temperature - absolute boiling. This is the value at which the thin boundary between the gas and the substance in the solid state disappears.
The next criterion, combining two neighboring aggregate states, is isotropy. In this case, their properties are the same in all directions. The crystals, in turn, are anisotropic. Like gases, liquids do not have a fixed shape and occupy the entire volume of the vessel in which they are located. That is, they have low viscosity and high fluidity. Colliding with each other, microparticles of liquid or gas make free movements. It used to be that there was no orderly movement of molecules in the volume occupied by the liquid. Thus, liquid and gas were opposed to crystals. But as a result of subsequent studies, the similarities between solids and liquids were proved.
In the liquid phase at a temperature close to solidification, thermal motion resembles motion in solids. In this case, the liquid can still have a certain structure. Therefore, giving an answer to such a question, how are particles located in solids in liquids and gases, we can say that in the latter the movement of molecules is chaotic, disordered. but in solids, molecules in most cases occupy a certain, fixed position.
In this case, the liquid is a kind of intermediate link. Moreover, the closer its temperature to boiling, the more molecules move as in gases. If the temperature is closer to the transition to the solid phase, then the microparticles begin to move more and more orderly.
Substance Change
Consider the simplest example of a change in the state of water. Ice is a solid phase of water. Its temperature is below zero. At a temperature equal to zero, the ice begins to melt and turns into water. This is due to the destruction of the crystal lattice: when heated, the particles begin to move. The temperature at which a substance changes its state of aggregation is called the melting point (in our case, it is 0 in water). Note that the temperature of the ice will remain at the same level until it melts completely. In this case, the atoms or molecules of the liquid will move in the same way as in solids.
After that, we continue to heat the water. The particles begin to move more intensively until our substance reaches the next point of change in the state of aggregation - the boiling point. Such a moment occurs when bonds between the molecules forming it due to the acceleration of motion break - then it acquires a free character, and the liquid under consideration passes into the gaseous phase. The process of transforming a substance (water) from a liquid phase into a gaseous phase is called boiling.
The temperature at which water boils is called the boiling point. In our case, this value is 100 degrees Celsius (temperature is dependent on pressure, normal pressure is one atmosphere). Note: until the existing liquid completely turns into steam, its temperature remains constant.
The reverse process of the transition of water from a gaseous state (vapor) to a liquid, which is called condensation, is also possible.
Then you can observe the freezing process - the process of transition of a liquid (water) into a solid form (the initial state described above is ice). The processes described earlier provide a direct answer to how particles are located in solids, in liquids and gases. The location and state of the molecules of a substance depends on its state of aggregation.
What is a solid? How do microparticles behave in it?
A solid is a state of the material environment, the distinguishing feature of which is to maintain a constant shape and constant nature of the thermal motion of microparticles that make minor fluctuations. Bodies can be in solid, liquid and gaseous state. There is also a fourth state, which modern scientists are inclined to classify as aggregate - this is the so-called plasma.
So, in the first case, any substance, as a rule, has a constant unchanged shape, and this is influenced by how the particles are located in solids. At the microscopic level, it can be seen that the atoms that make up a solid are connected to each other by chemical bonds and are located in the nodes of the crystal lattice.
But there is an exception - amorphous substances that are in a solid state, but cannot boast of the presence of a crystal lattice. It is on the basis of this that we can give an answer to how particles are located in solids. Physics in the first case indicates that atoms or molecules are located in lattice sites. But in the second case there is certainly no such ordering, and such a substance is more like a liquid.
Physics and the possible structure of a solid
In this case, the substance seeks to maintain its volume and, of course, shape. That is, in order to change the latter, efforts must be made, and it does not matter whether it is a metal object, a piece of plastic or plasticine. The reason is its molecular structure. And more precisely, in the interaction of the molecules that make up the body. They are in this case located most closely. This arrangement of molecules is repeating. That is why the forces of mutual attraction between each of these components are very large.
The interaction of microparticles explains the nature of their movement. It is very difficult to correct the shape or volume of such a solid body in one direction or another. Particles of a solid body are unable to randomly move throughout the entire volume of a solid body, but can only oscillate near a certain point in space. Molecules of a solid body oscillate randomly in different directions, but stumble upon themselves like ones who return them to their original state. That is why particles in solids are usually located in a strictly defined order.
Particles and their location in a solid
Solids can be of three types: crystalline, amorphous and composites. It is the chemical composition that affects the arrangement of particles in solids.
Crystalline solids have an ordered structure. Their molecules or atoms form a crystalline spatial lattice of the correct form. Thus, a solid in a crystalline state has a definite crystal lattice, which, in turn, sets certain physical properties. This is the answer to how particles are located in a solid.
Here is an example: many years ago, in St. Petersburg, a stock of white shiny tin buttons was stored in a warehouse, which, when the temperature dropped, lost its luster and turned white from gray to gray. Buttons crumbled into gray powder. "Tin plague" - this is what this "disease" was called, but in fact it was a restructuring of the crystal structure under the influence of low temperature. Tin, when switching from a white variety to gray, crumbles into powder. Crystals, in turn, are divided into single and polycrystals.
Single crystals and polycrystals
Single crystals (table salt) are single homogeneous crystals represented by a continuous crystal lattice in the form of regular polygons. Polycrystals (sand, sugar, metals, stones) are crystalline bodies that grow together from small, randomly arranged crystals. In crystals, a phenomenon such as anisotropy is observed.
Amorphous: special case
Amorphous bodies (resin, rosin, glass, amber) do not have a clear strict order in the arrangement of particles. This is a non-standard case of the order in which particles are in solids. In this case, the phenomenon of isotropy is observed, the physical properties of amorphous bodies are the same in all directions. At high temperatures, they become similar to viscous liquids, and at low temperatures they look like solids. With external action, elastic properties are simultaneously detected, that is, when impacted, they break into tiny particles, like solids, and fluidity: with prolonged temperature exposure, they begin to flow like liquids. They do not have specific melting and crystallization temperatures. When heated, amorphous bodies soften.
Examples of amorphous substances
Take, for example, ordinary sugar and find out the location of particles in solids in various cases, using his example. In this case, the same material can occur in crystalline or amorphous form. If the molten sugar hardens slowly, the molecules form even rows - crystals (lump sugar, or granulated sugar). If molten sugar, for example, is poured into cold water, cooling will occur very quickly, and the particles will not have time to form the correct rows - the melt will harden without forming crystals. So it turns out sugar candy (this is non-crystalline sugar).
But after some time, such a substance can recrystallize, particles are collected in regular rows. If the sugar candy lays down for several months, it will begin to become covered with a loose layer. So crystals appear on the surface. For sugar, the period will be several months, and for stone - millions of years. A unique example is carbon. Graphite is crystalline carbon, its structure is layered. And diamond is the hardest mineral on earth, able to cut glass and cut stones, it is used for drilling and polishing. In this case, the substance is one - carbon, but the peculiarity lies in the ability to form different crystalline forms. This is another answer to how particles are located in a solid.
The results. Conclusion
The structure and arrangement of particles in solids depends on what type the substance in question belongs to. If the substance is crystalline, then the arrangement of microparticles will be ordered. Amorphous structures do not possess such a feature. But composites can belong to both the first and second groups.
In one case, the liquid behaves similarly to a solid (at a low temperature, which is close to the crystallization temperature), but can also behave like a gas (when it increases). Therefore, in this review material, it was considered how the particles are located not only in solids, but also in other basic states of aggregation of matter.