Every chemical element observed or found in the periodic table is made up of atoms, which, in turn, are made up of protons, neutrons, and electrons. Remember that electrons are particles that have a negative charge and are located around the nucleus of any atom.
The way the electrons are organized in the electron shells of the atom is called energy sublevels; Its distribution in the atom or molecule is taken into account. In turn, these sublevels are called orbitals.
What are orbitals?
- Electron orbitals are defined as the volume around space and the probability that an electron should be found, which is 95%.
- The greatest probability of finding electrons is in the first orbital of an atom and in each orbital a maximum of two electrons can be located.
- The free and time-independent position of an electron in the molecule can also be represented by the orbitals.
How these electrons are organized into sublevels is what defines the position they occupy in the periodic table and, more importantly, what allows us to make chemical combinations of atoms.
There are different types of orbitals, with different shapes:
Designated by the letters S, P, DYF, that is to say acute, beginner, diffuse and fundamental; unite to form larger molecules.
Orbital combinations are observable in each shell of the atom:
- Layer 1: “S” orbitals.
- Layer 2: “S and P” orbitals.
- Layer 3: “S, P and D” orbitals.
- Layer 4: All “SP, D and F” orbitals.
Within the periodic table, each orbital is represented as specific blocks.
It has spherical symmetry around the nucleus of the atom. The block of this orbital is the alkali metal region, where we find: Lithium, Rubidium, Potassium, Sodium, Francium and Cesium; It is formed by the first group of the periodic table, including hydrogen, although it is not a metal but a gas.
This group belongs to the most active and reactive metals, they have only one electron which is usually lost to give rise to the formation of a positively charged ion.
In the case of hydrogen, it can form ions with a single positive charge, however, under high pressure it becomes metallic and behaves like the other elements of the group.
It represents the energy that an electron possesses. According to data collected on Wikipedia, its geometric shape is that of two spheres flattened towards a point of contact called “atomic nucleus”. Imagine two balls in which their flat part will be the atomic nucleus and the shape that this union will obtain will be its orientation according to the coordinate axes.
The elements of this block are characterized by valence electrons. Among the elements of this block are:
- Galio, among others; They are located in groups III-A VII-A of the periodic table.
In this sublevel we find 5 orbitals, which have different orientations. According to the data collected from Wikipedia, 4 of them have shapes of 4 lobes of alternating signs and a last orbital which apparently has 2 lobes surrounded by a ring.
In the periodic table, some of the elements belonging to this block are:
- Among others.
At their outermost energy levels they have two S electrons, and at their innermost levels they have F electrons and sometimes D electrons at intermediate levels.
In the periodic table, they are called internal transition or F-block elements. They are called lanthanum and actinides.
Among the elements of this block we can find:
- Among others.
Location of electron in orbitals
In the orbitals of an atom, electrons meet to lower the energy. In case they want to increase it, they will move away from the nucleus of the atom after filling the main orbital levels.
There are different rules that determine the position of these electrons, they are:
- Pauli’s Exclusion Principle: states that an orbital can describe at least two electrons in the atom.
- Aufbau Principle: It is based on energy level diagrams and basically what it says is that electrons first enter orbitals with lower energy.
- Hund’s rule: states that electrons first enter empty orbitals when electrons occupy orbitals of the same energy.