The first basic notion of chemistry concerns the distinction of the states of matter (solid, liquid and gaseous). Solid bodies have a volume and a well-defined shape. These two elements vary a little according to temperature and pressure.
Liquids occupy a specific volume, as they take the shape of the container that contains them. Gases tend to occupy the entire space available to them and their volume varies greatly with temperature and pressure .
In order to interpret the physical properties of any body, you must resort to the kinetic molecular theory. This indicates that all matter is composed of particles in continuous motion.
Random arrangement of particles
In a solid, the particles ( atoms and molecules) have a regular structure and can only move around their position. This would motivate the rigidity and fixed volume.
In liquids, we find a random arrangement of particles. In a gas, the atoms and molecules appear very far apart and move quickly. The higher the temperature , the faster the particles move.
The energy of motion (also called kinetic energy ) opposes the attractive forces of the molecules. When the temperature increases, we observe the changes of state that you can discover by continuing to read.
Vaporization process
If it experiences a very strong increase in temperature, a solid can transform into a liquid through fusion. If the heat were to increase further, the liquid could undergo a process of vaporization and pass into a gaseous state.
It is important to point out that a change of state can also occur in the case of thermal reduction. If the temperature drops, the gas can reconvert into a liquid through liquefaction or condensation. To reach the solid state, the liquid undergoes a solidification process: an example is steam that first becomes water and then ice.
There are two other phase transitions. When a solid passes directly into the gaseous state, we will have sublimation. The reverse transition is called frosting.
Electric charge
Matter has a molecular structure, so substances are formed by molecules (small mass). The latter are composed of atoms and when there are at least two of them that are not equal to each other, we can speak of a compound.The atom comes from the Greek “àtomos” (indivisible) and is made up of protons, neutrons and electrons. In these elements we find mass, which manifests itself with inertia and gravitational force.
The latter (always positive) is possessed by all three particles. The electric charge (negative or positive), on the other hand, is manifested by the electric force and is found only in protons and electrons. Neutrons, as one can imagine from their name, are neutral particles.
Octet rule
In any chemical process, the total mass of the bodies participating in the reaction remains unchanged (law of conservation of mass) and so does the algebraic sum of the charges (law of conservation of charge).Atoms tend to have orbitals with 8 electrons. To satisfy the octet rule, these elements tend to gain or lose electrons. Atoms can be grouped into three categories in the periodic table .
Metallic elements donate electrons, nonmetallic elements gain electrons, and noble gases tend not to react. Valence electrons are those involved in bonding, while inner electrons are not.
Coordination bond
Among the chemical bonds you must know the covalent one, which consists of the overlapping of two orbitals belonging to two atoms, each of which shares a valence electron.
The coordination (or dative) bond is a special covalent bond where both electrons shared come from only one of the two atoms. The ionic bond has electrical characteristics.
Once you know the strong chemical bonds, you will have to focus on the secondary (or weak) ones. Specifically, dipole-dipole, ion-dipole and hydrogen bond.
