properties of gases

Groups: A vertical column in the periodic table is termed as a group or family. They are considered to be the most important method of classifying the elements. In some groups, the elements have same properties and show a clear pattern in properties down the group. These groups are to be given trivial names, like the alkali metals, alkaline earth metals, halogens, and noble gases. Some groups in the periodic table show less similarities and these have no trivial names and are simply recognized by their group numbers.Periods: A horizontal row in the periodic table can be defined as a period. Although groups are the common way of classifying elements, there are some regions of the periodic table where the periods are more significant than groups. This can be true in case of d-block or "transition metals", and especially for the f-block, where the lanthanides and actinides form two horizontal series of elements.Blocks: Due to the importance of the outermost shell, blocks can be refered by the different regions of the periodic table, and are named according to the subshell in which the "last" electron is present. The s-block comprises the alkali metals and alkaline earth metals as well as hydrogen and helium. The p-block comprises the groups 13 through 18 and contains all of the semimetals. The d-block comprises groups 3 through 12 and has all of the transition metals. The f-block is comprised of the rare earth metals.Other: The chemical elements are also grouped together in many different ways. Some of these groupings are often stated on the periodic table, like transition metals, poor metals, and metalloids. Other groupings may also be present, which are informal like the platinum group and the noble metals.