While formation of simple molecules could be explained adequately by overlap of atomic orbitals, the formation of molecules of Be, B and C present problems of greater magnitude having no solution with the previous theory. To explain fully the tendency of these atoms to form bonds and the …
Read More »Physical Chemistry book , 3rd edition by Robert G. Mortimer
preface of This book The book is divided into four parts. The first part focuses on the macroscopic properties of physical systems. It begins with the descriptive study of gases and liquids, and proceeds to the study of thermodynamics, which is a comprehensive macroscopic theory of the behavior …
Read More »Fundamentals of electrochemistry book, 2nd edition by V.S. Bagotsky
preface of This book Two very important fields of natural science—chemistry and the science of electricity— matured and grew vigorously during the first half of the nineteenth century. Electrochemistry developed simultaneously. From the very beginning, electrochemistry was not merely a peripheral field but evolved with an important …
Read More »Bond Formation, (σ) Bond and (π) Bond
Bond Formation (Valence Bond Theory) – Bond formation between atoms to give chemical compounds can be interpreted admirably in terms of the orbital theory of atomic structure. – Heitler and London believed that electron cloud of the valence orbital on one atom ‘overlaps’ the electron cloud of the other bonding …
Read More »Multiple Choice Questions On Chemical bonding
1. The valency of an element is ___________ (a) the combining capacity of one atom of it (b) the number of bonds formed by its one atom (c) the number of hydrogen atoms that combine with one atom of it (d) all the above Answer. (d) 2. The …
Read More »VSEPR Theory (Valence-Shell Electron Pair Repulsion Theory)
VSEPR Theory ** The Lewis structure of a molecule tells us the number of pairs of electrons in the valence shell of the central atom. These electron pairs are subject to electrostatic attractions between them. On this basis, R.G.Gillespie (1970) proposed a theory called the Valence-Shell Electron Pair …
Read More »Bond Dissociation Energy
Bond Dissociation Energy ** Bond breaking can be quantified using the bond dissociation energy. **The bond dissociation energy is the energy needed to homolytically cleave a covalent bond. ** The energy absorbed or released in any reaction, symbolized by ΔH°, is called the enthalpy change or heat …
Read More »Metallic Bonding
Metallic Bonding ** The valence bonds that hold the atoms in a metal crystal together are not ionic, nor are they simply covalent in nature. Ionic bonding is obviously impossible here since all the atoms would tend to give electrons but none are willing to accept them. Ordinary …
Read More »Polar Covalent Bonds
Polar Covalent Bonds ** In the H2or Cl2 molecule, the two electrons constituting the covalent bond are equally shared by the two identical nuclei. Due to even distribution of (+) and (–) charge, the two bonded atoms remain electrically neutral. Such a bond is called nonpolar covalent bond. ** …
Read More »Hydrogen Bonding (H-Bonding)
Hydrogen Bonding – (H-Bonding) ** When hydrogen (H) is covalently bonded to a highly electronegative atom X (O, N, F), the shared electron pair is pulled so close to X that a strong dipole results ** Since the shared pair is removed farthest from H atom, its …
Read More »Co-ordinate Covalent bond
Co-ordinate Covalent bond ** In a normal covalent bond, each of the two bonded atoms contributes one electron to make the shared pair. ** In some cases, a covalent bond is formed when both the electrons are supplied entirely by one atom. Such a bond is called co-ordinate covalent …
Read More »Covalent Bond
Covalent Bond ** The electron transfer theory could not explain the bonding in molecules such as H2, O2, Cl2 etc., and in organic molecules, that had no ions. ** It was G.N. Lewis who suggested that two atoms could achieve stable 2 or 8 electrons in the outer shell by …
Read More »Ionic Bond
Ionic Bond ** This type of bond is established by transfer of an electron from one atom to another. ** Let us consider a general case when an atom A has one electron in the valence shell and another atom B has seven electrons. A has one electron …
Read More »Important Terms and Definitions in Chemical Bonding
Chemical Bond ** Molecules of chemical substances are made of two or more atoms joined together by some force, acting between them. This force which results from the interaction between the various atoms that go to form a stable molecule, is referred to as a Chemical Bond. ** A …
Read More »Multiple Choice Questions On Nuclear Chemistry – Part 1
1. Which is the correct symbol for an alpha particle? (a) 4He2 (b) 1n0 (c) 0e-1 (d) 1p1 Answer. (a) 2. Of the following, which is the most damaging when ingested? (a) beta emitters (b) alpha emitters (c) gamma emitters (d) all of these Answer. (b) 3. An …
Read More »Nuclear Fusion Process
Nuclear Fusion Process ** This process is opposite of nuclear fission. ** Nuclear fusion may be defined as : the process in which two light-weight nuclei combine or fuse to form a single heavier nucleus. ** The following figure shows Illustration of fusion of two deuterium (2H1) nuclei to form …
Read More »Nuclear Reactor
Nuclear Reactor ** It has been possible to control fission of U-235 so that energy is released slowly at a usable rate. ** Controlled fission is carried out in a specially designed plant called a nuclear power reactor or simply nuclear reactor. ** The chief components of a nuclear reactor are: (1) U-235 …
Read More »Nuclear Fission Process
Nuclear Fission Process ** In 1939, Hahn and Stassmann discovered that a heavy atomic nucleus as of uranium-235 upon bombardment by a neutron splits apart into two or more nuclei. U-235 first absorbs a neutron to form an unstable ‘compound nucleus’. The excited ‘compound nucleus’ then divides into …
Read More »Free download Concise Physical Chemistry book by Donald W.Rogers
Book preface and the author words Physical chemistry stands at the intersection of the power and generality of classical and quantum physics with the minute molecular complexity of chemistry and biology. Any molecular process that can be envisioned as a flow from a higher energy state to a …
Read More »Free Download Electrochemistry book (Principles, Methods, and Applications)
Book preface and the authors words Electrochemistry has undergone significant transformations in the last few decades. It is not now the province of academics interested only in measuring thermodynamic properties of solutions or of industrialists using electrolysis or manufacturing batteries, with a huge gulf between them. It has …
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