how the electronegativies of the elements generally vary within the periods and within groups of the table in the periodic table

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..

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 c..

Dobereiner's Triads - In the famous atomic theory of John Dalton (1805), it was suggested that the atoms of an element have a characteristic mass. So, attempts were made to classify elements on the basis of their atomic masses. In the year 1829, Johann Wolfgang Dobereiner, a Ger..

. In this table, the elements are arranged in the order of increasing atomic numbers in such away that elements with similar properties fall in the same vertical column. These vertical columns are referred to as 'Groups'. There are eight groups, whi..

There are seven periods in the periodic table and each period starts with a different principal quantum number. The first period corresponding to 'n' = 1 consists of only two elements hydrogen (1s 1 ) and helium (1s 2 ). This is because t..

1. Oxygen is the first member of the group VIA and sulphur is the second member of the group VI..

With developments on the structure of atoms, it was discovered that the atomic number (Z) is the important characteristic of the atom and not the atomic mass. This led to the development of the modern periodic law by Moseley in 1942. The modern periodic law states that "the phys..

Group A 1A 2A 3A 4A 5A 6A 7A 0 Period 1 1 H 2 He Period 2 3 Li 2,1 4 Be 2,2 5 B 2,3 6 C 2,4 7 N 2,5 8 O 2,6 9 F 2,7 10 Ne 2,8 Period 3 11 Na 2,8,1 12 Mg 2,8,2 13 Al 2,8,3 14 Si ..

Summary - The grouping of elements with similar properties together and the separation of elements with dissimilar properties is known as classification of elements. The table, which classifies elements on the basis of their properties, is..

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 ..