An Atom is the smallest particle that something can be broken down into and still retain the original chemical properes. Some examples include: Sodium (Na), Oxygen (O), Carbon (C)

Atomic model[]

They have been modeled to be like a solar system in miniature. There are electrons which revolve around a nucleus. That nucleus is made up of protons and neutrons. Different from the solar system, the electrons are not found in exact positions, they are in a wave-funcion position. That is, scientist can only predict a level of energy in which they are, not the real position. Also, the principle of uncertainty limits this knowledge.

There is a lot of empty space between the nucleus and the electrons. The electrons are placed in levels of energy. If a foton hits the electron, the atom gains energy. When the atom loses energy, it loses it in the form of a photon too, which is the lest quantity of energy an object can emit, according to Quantum Theory.

Atoms form molecules[]

Atoms join with other atoms to form molecules. They join by means of the electrons. The bonds can be:

  • Electronic bond: the electrons are taken by an atom
  • Covalent bond: the atoms share the electrons

There are two types of molecules that can be formed:

  • Organic molecules: they include molecules made with carbon, due to its capability of multiple bonds. They are found in life organisms. Organic chemistry is the chemistry of living things. Examples are: sugar, aminoacids, proteins, nucleic acids.
  • Inorganic molecules: like water (H20), salt (NaCl).