Developments in physics, chemistry and our understanding of how substances work have lead to the modern atomic model, which describes atoms by referring to the number of electrons within them. An atom therefore cannot be described using the modern atomic model, without knowing which element the atom is made of, as the element determines the number and arrangement of electrons in an atom.
Anything that you can feel or touch is made up of atoms. Atoms are the tiniest possible pieces of a particular element. Atoms of different elements can be combined in hundreds of different ways in order to create different substances with different properties. Scientists are always creating new substances for different purposes, as it is possible to replace single atoms with other atoms in order to create a whole new substance.
Atoms are basically made up of three parts - protons, neutrons and electrons. Electrons are tiny particles which surround the nucleus (center) of an atom - in fact, electrons are the smallest parts of an atom. Each electron carries a negative charge. The way that electrons are arranged around the nucleus of an atom dictates the way the atom as a whole functions and how the atom works.
- How are electrons arranged
Electrons are arranged around the nucleus in "shells" - circular paths around the outside of the nucleus. Every shell of electrons has a limit to the number of electrons it can contain. So, for example, if a shell had a limit of eight electrons, but an atom had a total of nine electrons, then eight electrons would sit in the first shell, and another shell would contain the remaining one electron. For scientists, electrons, shells, and the manipulation of electron formation are areas of constant development and study.
