To study the properties of cathode rays systematic investigations were made by W. Crooks, J.J. Thomson and J. Perrin. They established the following properties of cathode rays: Cathode rays are negatively charged. In 1895, J.Perrin showed that cathode rays are deflected in a magnetic field perpendicular to the line joining the two poles. In 1897,…
Discharge tube The discharge tube is a glass tube having two electrodes sealed into it connected to a vacuum pump to reduce the pressure of the gas taken into it. A slit is placed in the tube to get a sharp beam of radiations. Experiment: William Crooks a British scientist studied the passage of electricity…
“The solids having metallic bonds in them are called metallic solids.” Electron Gas Theory: The first theory of metallic bonding is called electron pool or electron gas theory. This theory was proposed by Drude and extended by Loren (1932). According to this theory, each atom in a metal crystal loses all of its valence electrons….
“The crystals consisting of molecules, which are held together through Vander Waals’ forces, are called molecular crystals.” Explanation: Since Van der Waals’ attractive forces are weaker, therefore, molecular crystals are soft and have low melting points and low lattice energies. These crystals are poor conductors of electricity. This is because electrons are bound to individual…
Diamond is crystalline (Allotropy) carbon. In the outermost shell of carbon, which is four, the atomic orbitals (1s and 3p) undergo sp3 hybridization to give four sp3 hybridized orbitals which are directed in space along the four corners of a tetrahedron. This is the unit cell of diamond and a large number of such unit…
“Covalent solids are also called atomic solids because they are composed of neutral atoms of the same or of different elements. These atoms are held together by covalent bonds:” When the covalent bonds give joint molecules like diamonds, silicon carbide or aluminium nitride. When atoms join to form the covalent bonds and separate layers are…