EducationThe science

What are valence electrons?

Teachers of physics and chemistry in educational institutions are well aware that it is much easier to explain a topic by resorting to analogies or using approximate examples, explaining "on the fingers." Although the descriptions given may not fully correspond to the generally accepted model, nevertheless, such an approach gives its results. This is the case in atomic physics.

The chemical properties of substances are relatively easy to explain, if we use the theory of atomic structure, proposed in 1911 by the English physicist E. Rutherford. Despite the fact that his model is only partially true, it is quite enough to understand the processes that are taking place. Today we will talk about what are valence electrons and what their relationship is with the properties of the material being studied. But first, let us recall the planetary model of the structure of the atom.

Rutherford determined that the atom is not an indivisible particle, as previously thought, but consists of a heavy core in the center and electrons rotating around it. The electric charge of the nucleus is positive (+), and for electrons, in turn, negative (-). Eight years after the publication of his theory of the structure of the atom, Rutherford was able to conduct a unique, at that time, experience - to turn nitrogen into oxygen. The experiment consisted of "bombarding" the alpha particles with nitrogen atoms. After the collision, an oxygen atom was formed and an "extra" particle with a positive charge, later called a proton.

The theory has acquired a complete form: the nucleus includes protons, with the help of magnetic forces, retaining electrons in orbits. Since the atom is electrically neutral, and the proton and the electron are attracted, their total quantities are equal. In 1932, the physicist J. Chadwick discovered that in the core, apart from protons, there are particles without charge-neutrons. They are responsible for the mass. Depending on the energy of the electron, it can be at a different distance from the nucleus. Valence electrons are those negatively charged particles that:

  • Are at the maximum distance from the nucleus, in outer orbits;
  • Can interact with neighboring atoms.

Under the interaction it is necessary to understand the possibility to leave its atomic orbit or change the trajectory of motion.

Valence electrons are determined very simply - according to Mendeleyev's table. For basic elements (except for subgroups, since there are exceptions), the condition is true: the maximum number of valence electrons corresponds to the number of the group in which the element under study is located. An atom that has a large theoretical number of such particles, reluctantly gives them to other atoms, so it is an oxidizer (takes the missing). And, conversely, with a small group number, the valence electrons are easily given off by the element, interacting. In this case, we are talking about a reducing agent or a donor atom.

Valence electrons directly depend on the state of the atom. So, if one or another way informs him of an additional energy from outside (put into an excited state), then the orbit of valence particles will become larger.

The data on the valence of materials make it possible to actively use them, predicting the result. For example, chemical sources of electric current based on electrolytes use such elements that are able to give and receive electrons. Neutral material would be useless in this case. It is not difficult to guess that if all the external electron shells of an atom are filled, then such an element is chemically neutral and does not interact with other atoms (or the interaction force is so insignificant that it can be neglected). A vivid example of this is inert gases.

Similar articles

 

 

 

 

Trending Now

 

 

 

 

Newest

Copyright © 2018 en.birmiss.com. Theme powered by WordPress.