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)
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).