Periodic table Alkali metals definition chemistry

They tend to be softer and conduct more poorly than the transition metals. As their name implies, they have some of the characteristics of the transition elements. The post-transition elements are Al, Ga, In, Tl, Sn, Pb and Bi. The transition elements are metals that have a partially filled d subshell (CRC Handbook of Chemistry and Physics) and comprise groups 3 through 12 and the lanthanides and actinides (see below). Their characteristics are well described and consistent down the group. The alkaline earth metals have very high melting points and oxides that have basic alkaline solutions. The alkaline earth metals make up group 2 of the periodic table, from Be through Ra. Hydrogen is group 1 but exhibits few characteristics of a metal and is often categorized with the nonmetals. They have very similar behavior and characteristics. The alkali metals make up group 1 of the Table, and comprise Li through Fr. In our version of the table, we have chosen the most commonly accepted demarcations between these elements. For example, in some tables, Group 12 is is categorized with the post-transition metals, and in others, aluminum and tin are included characterized as Metalloids or poor metals. The dividing line between metals and non-metals is not hard and fast, thus the distinction between 'Post-transition metals' and 'Metalloids' is represented differently on different versions of the Periodic Table. Metal elements are usually good conductors of both electricity and heat. Elements can generally be described as either metals or nonmetals.

Periodic table Alkali metals definition chemistry