Using The Periodic Table
The Periodic Table is an arrangement of all the known chemical elements in an informative array. It was first devised and constructed in 1869 by the Russian chemist Dmitri Mendeleev to help illustrate commonalities in the various properties of elements.
The current configuration of the periodic table has evolved over the years in both structure, organization, and number of elements. It continues to convey a wealth of useful information about each of the more than 114 elements.
Each element box contains key information:
- The symbol is the element's abbreviated English or Latin name. (For example, 'H' for hydrogen or 'Au' for aurum — the Latin word for gold.)
- The atomic number represents the number of protons in an atom of that element.
- The atomic mass is the average mass of all isotopes (versions) of that element, in atomic mass units. (Isotopes differ within an element as having the same number of protons but different numbers of neutrons.) Atomic mass is sometimes referred to as atomic weight.
Each row of elements is called a period. The period number indicates the highest energy level an electron in that element occupies (in its natural or unexcited state).
Each column is called a group or family. Elements within the same group have the same number of valence electrons (electrons available for bonding) and will tend to behave similarly in chemical reactions.
Elements are also identified by type, which identifies some higher-level properties. Examples of types include Metals, Non-Metals, Transitional Metals, and Metalloids.
The electron configuration shows how an element's electrons are arranged within their energy shells, as shown in three-character codes. The first character indicates the energy level, the second is the sub-shell, and the third is the number of electrons in that sub-shell. Of the four sub-shell types, S can hold up to two electrons while P can hold up to six. The D sub-shell holds up to ten electrons, and the F sub-shell holds up to fourteen. (A chemical symbol in the electron configuration means the lower energy electrons are configured the same way as in the symbol indicated.)
Electronegativity is a measure of the ability of an element to attract electrons in a chemical bond. Atoms with similar electronegativities will tend to share electrons with each other, forming covalent bonds. However, if the electronegativity difference is too great, one atom will "steal" the electron from the other, forming an ionic bond.
Ever wonder how to actually use the periodic table of elements? Get a detailed overview of the various sections on the periodic table including electron shell configuration, atomic mass, chemical symbols, electronegativity, and more with this tutorial.