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In 1929, Somerfield stated to apply quantum mechanics to explain conductivity phenomenon in metal. He has improved the Drude - Lorentz theory by quantizing the free electron energy and retained the classical concept of free motion of electron at a random.   ASSUMPTIONS:- ·          The electrons are free to move within the metal like gaseous molecules. They are confined to the metal due to surface potential. ·          The velocity distribution of the free electrons is described by Fermi-Dirac Statistics because electrons are spin half particles. ·          The free electrons would go into the different energy levels by following Pauli’s exclusion Principle which states that no two electrons have same set of Quantum numbers. ·          The motion of electrons is associated with a complex wave called matter wave...

Hello Students, Do you know ---- Q: Why are the atomic orbitals of oxygen atom in the molecular orbital diagram of carbon monoxide, CO, lower than those of carbon? A: It is because the electronegativity of oxygen is larger than that of carbon. Q: Which halogen has the largest oxidizing power? A: Since the reduction potential of fluorine is the highest, its oxidizing power is the largest. Q: Describe the numerical tendency of electronegativities of the elements in the periodic table. A: They increase toward the right and decrease down the table. Namely, the electronegativity of alkali metal Cs is the smallest and that of fluorine F is the largest. # eCLASS   # PhysicsConcepts   # ChemistryConcepts   # ScienceConcepts   # CBSEScience   # ICSEScience   # NIOSClasses

Hello Stude nts, Do you know about the "Hydrogen Bonding" !!!! The very large difference in electronegativity between the H atom and the atom to which it is bonded combined with the very small size of a H atom and the relatively small sizes of F, O, or N atoms, leads to highly concentrated partial charges with these atoms. Molecules with F-H, O-H, or N-H moieties are very strongly attracted to similar moieties in nearby molecules, a particularly strong type of dipole-dipole attraction called hydrogen bonding. Examples of hydrogen bonds include HF…HF, H2O…HOH, and H3N…HNH2, in which the hydrogen bonds are denoted by dots. Hydrogen bonds are much weaker than covalent bonds, only about 5 to 10% as strong, but are generally much stronger than other dipole-dipole attractions and dispersion forces. For example : consider the trends in boiling points for the binary hydrides of group 15 (NH3, PH3, AsH3, and SbH3), group 16 hydrides (H2O, H2S, H2Se, and H2Te), and group 1...

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Do you k now a bout the Quantum Theory of Electrons in Atoms !!!! See,  The energy levels are labeled with an n value, where n = 1, 2, 3,…  So, generally speaking, the energy of an electron in atom is greater for greater values of n . This number, n , is referred to as the principle quantum number.   The principle quantum number defines the location of the energy level. It is essentially the same concept as the n in the Bohr atom description. Another name for the principal quantum number is the shell number. The shells of an atom can be thought of concentric circles radiating out from the nucleus. The electrons that belong to a specific shell are most likely to be found within the corresponding circular area. The further we proceed from the nucleus, the higher the shell number, and so the higher the energy level. The positively charged protons in the nucleus stabilize the electronic orbitals by electrostatic attraction between the positive charges of the protons a...

The kinetic theory of gases explains the  macroscopic  properties of gases like volume, pressure, and temperature, as well as  transport properties  such as  viscosity ,  thermal conductivity  and  mass diffusivity .   The theory for ideal gases makes assumptions like --- ·         The gas consists of very small particles known as molecules. This smallness of their size is such that the total  volume  of the individual gas molecules added up is negligible compared to the volume of the smallest open ball containing all the molecules. This is equivalent to stating that the average distance separating the gas particles is large compared to their  size .                            ·         These particles have the same  mass . ·         The ...