Today we’ll tell you what the energy level of an atom is when a person is confronted with this concept, and where it is applied.
School physics
People first meet the natural sciences at school. And if in the seventh year of study, children still find new knowledge in biology and chemistry interesting, then in high school they begin to be afraid of them. When the turn of atomic physics comes, the lessons in this discipline already inspire only an aversion to obscure 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 discover another treasure there. Today we will talk about one of the basic concepts of atomic physics, the structure of matter.
Indivisible, compound, 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 consists of the smallest particles.
In modern history, experiments in chemistry were carried out much earlier than physical studies. Scientists of the seventeenth and eighteenth centuries worked primarily to increase the military power of the 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 out: some elements cannot be separated beyond a certain level. Hence, 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 the study of the smallest particles of matter. For example, it was clear: an atom contains both positively and negatively charged components. But the structure of the atom was unknown: the location, interaction, weight ratio of its elements remained a mystery.
Rutherford set the experience of scattering alpha particles with a thin gold foil. He found out 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 alike. This explained the charge of atoms: an element could be added to them or removed. The equilibrium that maintained the neutrality of the entire system was disrupted, and the atom acquired a charge.
Electrons, Protons, Neutrons
Later it turned out: light negative particles are electrons, and a heavy positive nucleus consists of two 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 energy. But the atom divides the electron much easier. There are more electronegative atoms, which are more likely to "take" the electron, and less electronegative, which are more likely to "give" it. So the atom’s charge is formed: if there is an excess of electrons, then it is negative, and if there is a deficiency, then it is positive.
Long life of the universe
But such an atomic structure puzzled scientists. According to the dominant classical physics of the time, an electron that moved around the nucleus all the time had to continuously emit electromagnetic waves. Since this process means energy loss, all negative particles would soon lose their speed and fall to the core. However, the universe has been around for a very long time, and a global catastrophe has not yet occurred. The paradox of too old matter was brewing.
Postulates of Bohr
Bohr's postulates were able to explain the discrepancy. Then it was just statements, leaps into the unknown, which were not confirmed by calculations or theory. According to the postulates, there were energy levels of electrons in an atom. Each negatively charged particle could only be at these levels. The transition between the orbitals (the so-called levels) is carried out by a jump, while a quantum of electromagnetic energy is released or absorbed.
Planck's discovery of a quantum later explained this behavior of electrons.
Light and atom
The amount of energy needed for the transition depends on the distance between the energy levels of the atom. The farther they are from each other, the greater the emitted or absorbed quantum.
As you know, light is the quantum of the electromagnetic field. Thus, when an electron in an atom passes from a higher to a lower level, it creates light. In this case, the inverse law also applies: when an electromagnetic wave hits an object, it excites its electrons, and they transfer to a higher orbital.
In addition, the energy levels of an atom are individual for each type of chemical element. The pattern of the distances between the orbitals differs for hydrogen and gold, tungsten and copper, bromine and sulfur. Therefore, the analysis of the emission spectra of any object (including stars) unambiguously determines what substances and in what quantity are present in it.
This method is applied incredibly widely. Spectral analysis is used:
- in forensics;
- in monitoring the quality of food and water;
- in the production of goods;
- in the creation of new materials;
- in the improvement of technology;
- in scientific experiments;
- in the study of stars.
This list only roughly shows how useful the discovery of electronic levels in the atom turned out to be. Electronic levels are the coarsest, the biggest. There are smaller vibrational, and even finer 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 investigated. 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 a certain analogue of electronic levels. However, this has not yet been proven.