Today we will tell you about what the energy level of an atom is, when a person encounters this concept, and where it is applied.
School physics
People first encounter science at school. And if in the seventh year of study, children still find new knowledge in biology and chemistry interesting, then in the senior classes they begin to be afraid. When the turn of atomic physics comes, lessons in this discipline already inspire only disgust for incomprehensible tasks. However, it is worth remembering that all the discoveries that have now turned into boring school subjects have a non-trivial history and a whole arsenal of useful applications. Finding out how the world works is like opening a box with something interesting inside: you always want to find a secret compartment and find another treasure there. Today we will talk about one of the basic concepts of atomic physics, the structure of matter.
Indivisible, composite, quantum
From the ancient Greek language, the word "atom" is translated as "indivisible, smallest". This view is a consequence of the history of science. Some ancient Greeks and Indians believed that everything in the world was made up of tiny particles.
In modern history, experiments in chemistry were made much earlier than physicalresearch. Scholars of the seventeenth and eighteenth centuries worked primarily to increase the military power of a country, king or duke. And in order to create explosives and gunpowder, it was necessary to understand what they consist of. As a result, the researchers found that some elements cannot be separated beyond a certain level. This means that there are the smallest carriers of chemical properties.
But they were wrong. The atom turned out to be a composite particle, and its ability to change is of a quantum nature. This is evidenced by the transitions of the energy levels of the atom.
Positive and negative
At the end of the nineteenth century, scientists came close to studying the smallest particles of matter. For example, it was clear that an atom contains both positively and negatively charged components. But the structure of the atom was unknown: the arrangement, interaction, the ratio of the weight of its elements remained a mystery.
Rutherford set up an experiment on the scattering of alpha particles by thin gold foil. He found that in the center of the atoms are heavy positive elements, and very light negative ones are located at the edges. This means that the carriers of different charges are particles that are not similar to each other. This explained the charge of atoms: an element could be added to them or removed. The balance that kept the entire system neutral was broken, and the atom acquired a charge.
Electrons, protons, neutrons
Later it turned out: light negative particles are electrons, and a heavy positive nucleus consists oftwo types of nucleons (protons and neutrons). Protons differed from neutrons only in that the former were positively charged and heavy, while the latter had only mass. Changing the composition and charge of the nucleus is difficult: it requires incredible energies. But an atom is much easier to divide by an electron. There are more electronegative atoms, which are more likely to "take away" an electron, and less electronegative ones, which are more likely to "give" it away. This is how the charge of an atom is formed: if there is an excess of electrons, then it is negative, and if there is a shortage, then it is positive.
Long life of the universe
But this structure of the atom puzzled scientists. According to the classical physics that prevailed at that time, an electron, which was constantly moving around the nucleus, had to continuously radiate electromagnetic waves. Since this process means a loss of energy, all negative particles would soon lose their speed and fall on the nucleus. However, the universe has existed for a very long time, and the global catastrophe has not yet occurred. The paradox of too old matter was brewing.
Bohr's postulates
Bohr's postulates could explain the discrepancy. Then they were just assertions, jumps into the unknown, which were not supported by calculations or theory. According to the postulates, there were energy levels of electrons in the atom. Each negatively charged particle could only be at these levels. The transition between orbitals (the so-called levels) is carried out by a jump, while a quantum of electromagnetic energy is released or absorbed.energy.
Later, Planck's discovery of the quantum explained this behavior of electrons.
Light and atom
The amount of energy required for the transition depends on the distance between the energy levels of the atom. The farther they are from each other, the more emitted or absorbed quantum.
As you know, light is the quantum of the electromagnetic field. Thus, when an electron in an atom moves from a higher to a lower level, it creates light. In this case, the reverse law also applies: when an electromagnetic wave falls on an object, it excites its electrons, and they move to a higher orbital.
In addition, the energy levels of the atom are individual for each type of chemical element. The pattern of distances between orbitals is different for hydrogen and gold, tungsten and copper, bromine and sulfur. Therefore, an analysis of the emission spectra of any object (including stars) unambiguously determines which substances and in what quantity are present in it.
This method is used incredibly widely. Spectrum analysis used:
- in forensics;
- in food and water quality control;
- in the production of goods;
- in creating new materials;
- in improving technology;
- in scientific experiments;
- in the exploration of the stars.
This list only roughly shows how useful the discovery of electronic levels in the atom has been. Electronic levels are the roughest, the largest. There are smallervibrational, and even more subtle rotational levels. But they are relevant only for complex compounds - molecules and solids.
It must be said that the structure of the nucleus has not yet been fully explored. For example, there is no answer to the question of why such a number of neutrons corresponds to a certain number of protons. Scientists suggest that the atomic nucleus also contains some analogue of electronic levels. However, this has not yet been proven.
