The halogens The halogens are located on the right side of the modern periodic table before the inert gases, The halogens are elements of group 7 A (17) in p-block, The halogens are mono-valent...
The alkali metals are located on the left side of the modern periodic table in the group (1) or (1 A). They are the first group of s-block, The alkali metals are mono-valent elements...
The species A species is a group of more similar living organisms in the shape that can reproduce to give birth of new fertile individuals which are able to reproduce and keep the existence...
The mammals The mammals are classified according to the kind and the number of teeth into the edentates mammals (The teethless mammals), and the mammals having teeth.
