valence theory

Drawbacks of Valence Bond Theory - 1) It is a qualitative approach describing bonding in coordination compounds. 2) The theory fails to explain the optical absorption spectra and magnetic properties of coordination compounds. 3) The theory does not provide an..

1) It is a qualitative approach describing bonding in coordination compounds. 2) The theory fails to explain the optical absorption spectra and magnetic properties of coordination compounds. 3) The theory does not provide an answer to the origin of characteristic colors of compl..

Main Postulates - I) The metal ligand bond arises by donation of pair of electrons by ligands to the central metal atom. II) To accommodate these electrons the metal ion must possess requisite number of vacant orbitals of equal energy. These orbitals of the metal atom undergo hybridisation to give ..

The VSEPR theory, proposed by R.J.Gillespie and R.S. Nyholmm in 1957, is based on the repulsions between the electron-pairs in the valence-shell of the atoms in the molecule. It was developed to predict the shapes of the molecules in which the atoms are bonded together wit..

Contractile proteins of membrane show their existence in folded or unfolded condition. Proteins in unfolded conditions are able to bind ions by free valencies exposed at membrane surface. Proteins in folded (contracted) condition release ions as free valencies of proteins get s..

Quantum Theory of Covalent Bond - Although the Lewis structures give an idea of the valence electrons around the atom, in reality it does not precisely locate the position of the electrons in the chemical bond. The behaviour of electrons in molecules and compounds is made by the..

Dalton's Atomic Theory - John Dalton provided a simple theory of matter to provide theoretical justification to the laws of chemical combinations in 1805. The basic postulates of the theory are: All substances are made up of tiny, indivisible particles called atoms. At..

. As a result, a large number of energy levels are crowded together into 'bands'. Because of these energy bands, the molecular orbital theory of metals is also known as band theory. As an illustration the bonding in sodium metal can be studied. Imagine that a crystal of sodium i..

Determination of the Structure of a Complex Using Werner's Theory - Example: In the complex between CoCl 3 and NH 3 the ionizable chloride ions are found by precipitation with AgNO 3 . The remaining Cl and NH 3 are present around the central Co in such directions so as to minimize repulsi..

Example: In the complex between CoCl 3 and NH 3 the ionizable chloride ions are found by precipitation with AgNO 3 . The remaining Cl and NH 3 are present around the central Co in such directions so as to minimize repulsion and are linked by secondary valencies. a) Primary valenciesh..