Overview of Atoms
Atoms are the smallest articles that comprises a chemical element. Each atom is made up of an electron cloud that surrounds a dense nucleus.
Each nucleus consists of positively charged protons electrically neutral neutrons, the opposite of the cloud that is made up of negatively charged electrons. The atom is only electrically neutral when there are the same amount of protons in the nucleus as there are electrons. If the number of protons and electrons in the nucleus are not the same the atom is either positively or negatively charged, and the atom is always categorized by the number of protons and neutrons. The chemical element is determined by the number of protons vise versa the isotope of the element is determined by the number of neutrons. The people who thought of an atom as an invisible thing that makes up all matter was the early Indian and Greek philosophers. The Indian and Greek philosophers were thinking this up as early as the 17th and 18th centuries. This idea was first scientifically proved by chemists that showed some elements could not be further broken down by chemical methods. Later on in the 19th and 20th centuries it was proven that inside the atom were subtonic structures and components. This proved that the atom was actually not invisible, just too small for the human eye to see without the help of a very powerful microscope.
The part of the atom that has nearly all the mass is the nucleus. It has approximately 99.9% of the mass of the atom. Depending on the number of electrons and protons compared to the number of nuclei the atom may be subject to radioactive decay. However this is not the case with all atoms.
The idea of little tiny substances making up all matter has been around forever. However most of these theories were way off. They wee thought up philosophically not experimentally. This idea was first brought up in India in the 6th century BCE. They thought up of complex ways of how these invisible things came together to produce all elements. Though these early theories were a long ways off of how atoms really work many of the names thought up by Democritus and his early fellow philosophers have been kept by modern scientists.
As you can tell these very small things are not a recent idea. However they are very complex and there are vast amounts of information still to be recovered from them. The reason they are so hard to study is because they are so small. But that did not turn back early scientists, so why should it turn back modern scientists?