groups of the periodic table

Representative elements are those elements whose inner shells are complete and whose outer shell (valency shell) has 1 to 7 electrons. They are also called normal elemen..

'. Elements with similar properties recurred at regular intervals and fell in certain groups or families. The elements in each group were similar to each other in many properties. The elements with dissimilar properties from one another were separated. Mendeleev's periodich..

In 1869, Mendeleev classified the then known 56 elements on the basis of their physical and chemical properties in the increasing order of the atomic masses, in the form of a table. Mendeleev had observed that properties of the elements orderly recur in a cyclic fashion. He found that th..

Main Features of Modern Periodic Table - 1. The modern periodic table is divided into two main categories: (i) Vertical columns called Groups and (ii) Horizontal columns called Periods. 2. There are 18 vertical columns or groups...

Hydrogen is the first element of the periodic table. Its atomic number is 1, which indicates the presence of only one electron in the atom of hydrogen. This electron is present in its first shell. Hydrogen resembles both alkali metals (group I A) as well as halog..

In 1869, Mendeleev classified the then known 56 elements on the basis of their physical and chemical properties by giving a law known as the periodic law. The name periodic law stems from the fact that the properties of the elements orderly recur in a cyclic fashion. His pe..

>The modern periodic table is also known as the long form of the periodic table or the extended form of the periodic table. In this table, the elements are arranged in the order of increasing atomic numbers in such away that elem..

The position of an element in the periodic table is generally determined by its electronic configuration e.g. electronic configuration of sodium is 2, 8, 1 i.e., it has three shells and one electron in the outermost shell. Hence, it is placed in period number 3 and ..

Position of Chlorine in the Periodic Table - 1.Chlorine is placed second after fluorine in group VIIA. 2. Other members of this group are fluorine, bromine, iodine and astatine (the last member is radioactive). 3. Members of this group are called 'h..

Periodic Table and Valency of Elements - a) Group IA, IIA and IIIA consists of metals of normal elements. They have 1, 2, or 3 valence electrons which they can easily donate to acquire the configuration of nearest noble gas. They become positively charged i.e., cations..