Periodic Table

From HvWiki

A table listing all the elements, grouping similar ones together and giving basic information on each.

Information on a Periodic Table

Tables vary in their exact format, but mostly the elements look something like in the image.

The topmost number, 1, is the atomic number, the large letter below is the chemical symbol for the element, underneath is the common name for the element and lastly there is the atomic mass of the element.

Atomic Number

This is the number of protons in the element's nucleus. Every element has a unique atomic number. In a neutral atom, this is the same as the number of electrons.

Atomic Mass

This is the mass, in grams, of one mole of the substance. It's roughly the number of protons plus the number of neutrons. Individual atoms come in different isotopes (have different numbers of neutrons), so the atomic mass is the average of the masses of these isotopes, weighted by their relative abundance. For example, hydrogen mostly comes as an isotope with no neutrons, with an atomic mass of about 1, but there also exist other isotopes with neutrons, such as deuterium, so the atomic mass is greater than one.