From Latin atŏmum, a atom is the smaller amount of a chemical element that has its own existence and that is considered as indivisible . The atom is formed by a nucleus with protons and neutrons and for several orbital electrons , whose number varies according to the chemical element.

However, in addition to the elements that compose it, it is important to underline that every atom has a series of properties that are essential to consider when working with it. In this case, we find the fact that they are the size, mass, electrical interactions that are established between electrons and protons or energy levels.

The atom is also referred to as the fundamental particle , thanks to its characteristic of not being able to be divided by chemical processes. From the 16th centuries and XVII , with the development of the chemistry Atomic theory began to advance with certainty that, until then, was impossible to obtain.

Chemists managed to discover that any liquid, gas or solid could be broken down into different elements or constituents (for example, each molecule of water is made up of two atoms of hydrogen and one of oxygen: H2O ). John dalton It was he who demonstrated that atoms joined together according to certain definite proportions.

However, there have also been other authors who, deeply and intensely, have left their mark on the study and analysis of atoms. This would be the case, for example, of the British scientist Joseph John Thomson. This went down in history not only as the inventor of the mass spectometer but also as the discoverer of two fundamental elements: the isotopes and the electron.

The New Zealand physicist Ernest Rutherford, the Danish Niels Bohr or the Frenchman Louis-Victor de Broglie are other scientists who, throughout history, have developed their own atomic theories and models with more or less success and acceptance by The scientific community.

In this case it is important to underline the role of the last physicist cited since in 1929 he won the Nobel Prize for having managed to discover the undulating nature of what the electron is.

We said at the beginning of this definition that the atomic nucleus is composed of protons and neutrons. The protons have a positive energy charge while neutrons no load . The difference between the different chemical elements is given by the amount of protons and neutrons of their atoms. On the other hand, the amount of protons contained in the nucleus of an atom is called atomic number .

The periodic table of elements It is an organization that allows to distribute the different chemical elements according to certain characteristics and criteria. The simplest core is that of hydrogen , which has a single proton. That is why it appears in the first place of the table. Hydrogen is followed by helium , which has two protons and two neutrons.

In addition to all of the above, we cannot ignore the existence of a colloquial expression that uses the term at hand. It is the expression "in an atom" that comes to be synonymous with "in the smallest thing."