Periodicity of valence or Oxidation State The electrons present in the outermost shell of an atom are called valence electrons and the number of these electrons determine the valence or the valency of the atom. The orbitals present in the valence shell are called valence orbitals. The valence of an atom equal to either the…
Read MoreCategory: Classification of Elements and Periodicity in Properties
Electronegativity
Electronegativity of an element is the tendency of its atoms to attract the shared pair of electrons towards itself in a covalent bond. The electronegativity of any given element depends upon the following factors: 1) State of hydridization A sp-hybridized carbon is more electronegative than sp2 hybridised carbon, which in turn is more electronegative than…
Read MoreElectron Gain Enthalpy
Electron gain enthalpy of an element may be defined as the energy released when a neutral isolated gaseous atom accepts an extra electron to form the gaseous negative Ion i.e. anion.It is denoted by Δ eg H. Greater the amount of energy released in the above process, higher is the electron gain enthalpy of the…
Read MorePrediction of period, group and block of a given element
The period of an element corresponds to the principal quantum number of the valence shell. The block of an element corresponds to the type of orbital which receive the last electron. The group of an element is predicted from the number of electrons in the valence shell or/and penultimate shell as follows: a)For s block…
Read MoreIonization Enthalpy
If sufficient energy is supplied ,electrons may be removed resulting in the formation of a positively charged ion. The minimum amount of energy required to remove the most loosely bound electron from an isolated gaseous atom so to convert it into gaseous cation is called ionisation enthalpy. It is represented by Δ i H This process…
Read MoreDivision of elements into s, p, d and f block
Elements in the long form of periodic table have been divided into four blocks i.e. s ,p ,d and f. This division is based upon the name of the orbitals which receives the last electron. S block elements 1)Elements in which the last electron enters the s orbital of their respective outermost shells are called…
Read MoreElectronic configuration Of Elements
1)The names are derived directly from the atomic numbers using numerical root for 0 and numbers from 1-9 and adding the suffix ium.The roots for the numbers 0-9 are: 2) In certain cases, the names are shortened.bi ium and tri ium are shortened to bium and trium and enn nil shortened to ennil. 3)The…
Read MoreModern Periodic Table
Modern periodic law states that physical and chemical properties of the elements are periodic function of the atomic numbers i.e.if the elements are arranged in order of their increasing atomic numbers, the elements with similar properties are repeated after certain regular intervals. Atomic mass depends upon the number of protons and neutrons in the nucleus…
Read MoreMendeleev’s Periodic Law And Table
He examined the relationship between atomic weights of the elements and their physical and chemical properties.Among chemical properties, Mendeleev mainly concentrated on the compounds formed by the elements with hydrogen and oxygen because they are highly reactive and hence formed compounds with almost all the elements. The formulae of the hydrides and oxides formed by…
Read MoreHistorical Development Of Periodic Table
Periodic table may be defined as the table which classified all the known elements in accordance with their properties in such a way that elements with similar properties are grouped together in the same vertical column and dissimilar elements are separated from one another. Doebereiner’s triad The first attempt towards the classification of elements was…
Read More