Atom - Explanation and defintion of atom

What is an atom

Atom as the smallest unit that makes a chemical element which consists of a core and a finite number of electrons surrounding it is currently defined.

Since the concept of the atom first developed in ancient Greece to the latest discoveries developed in particle accelerators latest technology, the concept and definition of the atom has changed dramatically.

The ancient Greek philosophers Leucippus and Democritus were the first to describe the atom as the minimum, indivisible unit which comprises all matter, this definition was revolutionary at the time since it was stated that everything around us was formed particle called a single atom.

The periodic table lists and classifies all known elements based on their atomic number or what is the same the number of protons in an atom, which becomes the basic unit of the periodic table. The atoms are joined together by chemical bonds in order to create more complex elements such as molecules, cells, tissues, organs ... so part of the ancient Greeks are right describing the atom as a unit which comprises all the matter around us.

Subsequently, different scientists reported various theories leading to the different atomic models which attempt to explain the properties and composition of the atom, examples and models of Dalton, Thomson, Rutherford and Bohr are used today to understand the elements and particles forming part of the atom.

Today we know that atoms are not indivisible, in fact we know are composed of electrons that spin and move around its nucleus, turn the core consists of neutrons and protons, which are made up of smaller particles called quarks.

The core comprised of neutrons to protons is 99.9% by weight of one atom occupying less space than 0.01% by volume, while electrons contribute only 0.01 weight% less space occupying 0 , 00001%, so we say that the atom is virtually empty. Moreover electrons provide the negative charge of the atom while the protons of the core provide the positive charge and neutrons have no charge, resulting in a balance of zero charge to be equal the number of electrons and protons, these elements that make up the atom are held together mediantes attractive forces (weak nuclear force, strong nuclear force and electromagnetic force), making them stable, resilient and enduring over billions of years.

Using particle accelerators, scientists discovered that the atom was composed not only by electrons, neutrons and protons but a large number of subatomic particles began to detect and discover new challenge now was to classify these subatomic particles as does the periodic table elements, that ultimately led to the development of the known standard model of particle physics, which describes two types of fundamental particles; bosons and fermions, which in turn are divided into groups known as quarks and leptons. Like the ancient Greeks we know the fundamental particles that make up matter.

Finally, string theory proposes that all matter and hence all elementary particles like quarks are each made up of extremely tiny strings or filaments which vibrate in a certain way to be directly responsible for the origin of all our universe , ie the strings is the smallest indivisible element which is the source of everything we know.

Now that you know what an atom is, did you know that in a single grain of sand contains 30.000 trillion atoms ?, you imagine how many atoms are in the universe...