electron configuration for the elements in the periodic table

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..

Later, Henry Gywn-Jeffreys Moseley showed that the atomic number of an element is numerically equal to the number of electrons round the nucleus. The number of electrons in turn is equal to the number of protons in the nucleus. He suggested that atomic number is a mor..

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. These are further s..

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..

Types of Elements - On the basis of electronic configuration, the elements of the periodic table are classified into: (1) Noble gases, (2) Normal elements, (3) Transition elements, (4) Inner-transition elements..

Because of their characteristic electronic configuration, the properties of transition elements ('d' block elements) in any period do not differ much from each other (unlike nontransition elements from the same period). The ..

Advantages of Long form Periodic Table - 1. The classification of elements is based on the atomic number, which is a more fundamental property. 2. The reason for placing isotopes at one place is justified as the classification is on the basis of atomic number. 3. It ex..

Grouping of Elements - In the long form of the periodic table, elements are grouped into four main blocks, purely on the basis of electronic configurations. Elements are grouped in blocks 's', 'p', 'd' and 'f' depending on the na..

In the long form of the periodic table, elements are grouped into four main blocks, purely on the basis of electronic configurations. Elements are grouped in blocks 's', 'p', 'd' and 'f' depending on the nature of orbital(s) into which the..

Third Row Elements - The third row elements are from sodium to argon. The build up of these eight elements proceeds exactly in the same manner as discussed above. Here 3s- and 3p-orbitals are filled in place of 2s- and 2p-orbitals as has been done in case of Li to Ne. ..