VALENCE SHELL ELECTRON PAIR REPULSION THEORY (VSEPR Theory) : VSEPR theory is based on the idea that electron pairs try to be far apart as possible in the central atom of a covalent molecule. The shape of molecules depends on the number and nature of electron pairs present in the valence shell of central atom of molecule. Postulates/Assumptions of VSEPR theory : 1.) In a covalent molecule or an ion, there is a central atom to which all other atoms are attached. 2.) Pair of electrons are present in the valence shell of central atom. They are of following types : a.) Bond pair : The pairs taking part in the reaction. b.) Lone pair : The pairs left out during bonded state. 3.) The repulsion between electron pairs are in the following order : Bond pair and Bond pair < Bond pair and Lone pair < Lone pair and Lone pair 4.) The shape of the molecule or the ion is the f
MAGNET : A magnet is a material which has its atoms arranged in such a way that it exhibits attractive and directive characters. Properties of Magnet : 1.) A magnet has attractive property . It can attract ferromagnetic materials like iron, nickel, cobalt and their alloys. The strength of attraction follows the inverse square law. Ferromagnetic materials : The substances like iron, below a certain temperature (curie point) can possess magnetization (magnetic property) in the absence of an external magnetic field. These substances are called ferromagnetic materials. 2.) A magnet's strength is concentrated in two poles i.e. North pole and South Pole . NOTE: Even if we break/cut a magnet, the broken pieces will also have both the poles. A magnet having only a single pole (magnetic monopole) has been theorized but has not been practically observed. 3.) The north poles of two magnets repel each other and north and