Elements
Elements are the smallest naturally occurring form of one kind of a chemical. In other words, they are the purest form of a chemical and do not contain any other substances. Elements are arranged into the periodic table which helps display chemical relationships between the elements. Ninety-two elements occur naturally. The remaining 20 must be artificially created. Elements are represented by chemical symbols. These symbols can represent names in English (H for Hydrogen), Latin (Ag for Argentum [silver]), ancient Greek or even be named after a well know person (Es for Einsteinium).
Atoms
All elements are made up of atoms, which are the smallest units of matter. Atoms in turn are made up of the following sub-atomic particles.
- Protons: Positively charged sub-atomic particles. Protons exist in the nucleus of an atom. Their weight is one atomic mass unit or 1 amu. An element always has the same number of protons as electrons.
- Neutrons: Neutral charged sub-atomic particles. Neutrons also exist in an atom nucleus. Neutrons also have a weight of 1 amu.
- Electrons: Negatively charged sub-atomic particles. Electrons float around in an electron cloud in orbits around the atom’s nucleus. Electrons are much lighter than either protons or neutrons having an atomic mass unit much less than one. An element always has the same number of electrons as protons.
- Protons and neutrons can be further broken up into even smaller particles such as quarks, bosons, mesons, etc..
Atomic number
The atomic number of an element is the number of protons in its nucleus. This defines the type of element it is, the family of elements to which it belongs and its position on the periodic table. An example of this would be carbon. Its atomic number is 6, which means its the only element with 6 protons in its nucleus. The lightest element, Hydrogen, with an atomic number of 1, is the only element with one proton in its nucleus. It is also the only element naturally containing no neutrons.
Atomic mass or weight
An element’s atomic mass (or atomic weight) is the number of the protons and neutrons in the atomic nucleus. By subtracting the atomic number from the atomic mass, the number of neutrons can be calculated.
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