The atomic radius is half the distance between the nuclei of two adjacent atoms joined by a covalent bond.
Radio is a notion with a large number of meanings according to the context. It may be the segment that links the circumference of a circle with its center, a bone in the human body, the spoke of a wheel, the device that captures radio waves and transforms them into sound, or a chemical element .
Atomic , for its part, is the adjective that qualifies that which is linked to an atom (the smallest amount of a chemical element that is indivisible and has its own existence).
Atomic radius concept
Having said all this, we can introduce ourselves to the concept of atomic radius . This notion refers to half the distance between the nuclei of two atoms that are adjacent and linked by a covalent bond, or to the distance between the outermost orbital of one and the nucleus of another.
The concept of an atomic orbital is defined as a particular time- and spatial-independent solution to the Schrödinger equation for an electron that is subjected to a Coulomb potential .
Thanks to the atomic radius, it is possible to calculate the size of atoms.
Complementary notions
Let's look at the three complementary concepts of this paragraph in more detail:
* the particular, or complete, solution is a case of the partial differential equation (PDE) that has the same number of independent variables as arbitrary constants. For its part, EDP is called the equation that has functions of different variables as unknowns, with the particularity of including the derivatives of said functions in the equation;
* The Schrödinger equation was created by an Austrian physicist of the same name at the beginning of the 20th century and serves to describe the evolution in time of a non-relativistic massive particle. In quantum mechanics , where it has a fundamental role, it allows microscopic particles to be associated with Newton's Second Law , also known as the Fundamental Law of dynamics , which defines that the variation of movement occurs in proportion to the driving force that is generated. prints and according to the straight line on which said force is oriented ;
* The Coulomb potential is part of the homonymous law, which, among other things, proportionally relates the electrical forces of two charges to the product of the magnitude of said charges. The Coulomb potential is a scalar function that is applied to facilitate the use of vector expressions involving electric charges and force fields.
Usefulness of atomic radius
Through the atomic radius, the size of the atom in question can be calculated; The size of the atoms, on the other hand, affects changes in state , density and other properties , such as melting and boiling points.
The attractive force that the nucleus exerts on the electrons determines the atomic radius. As the effective charge increases, the bond between the nucleus and the atoms becomes stronger and, therefore, the atomic radius becomes smaller. Conversely, when the charge decreases, the atomic radius increases.
Issues to consider
If we look at the periodic table , we will notice that the elements have greater atomic radii as we go down and to the left. This is because the atomic radius increases when a period decreases, while it decreases if a group advances.
It is important to highlight that it is possible to distinguish between covalent atomic radius (when the nuclei are at a distance that is equivalent to the result of adding their covalent radii) and metallic (when the atomic radius represents half of the segment that can be drawn between each nucleus in crystals). metallic). Despite this classification, the first case is the one that is used most frequently.