Skip to main content

Posts

Showing posts from November, 2022

alkanes

                 Alkanes   Alkanes  are hydrocarbons in which the carbon atoms are held together by single bonds.  Alkanes also called parafins. Their general formula is C n H 2n+2  for molecules which do not contain ring structures.Alkanes are also called saturates or saturated hydrocarbons. The carbon atoms that make up the carbon backbone are linked together to form a chain (linear or branched alkanes), a circle (cyclic alkenes), or a mixture of both. The alkanes are distinguished from the other hydrocarbons by the fact that they are completely saturated with hydrogen. This means that no additional hydrogen atoms can be added to these hydrocarbons without destroying the carbon backbone.  Alkanes are in some respect the most boring of the organic compounds, since they are unreactive (mostly) towards acids, bases, oxidizing agents, reducing agents, and most of the other reagents that organic chemistry have in their arsenals.  On the other hand, alkanes are important for their ability

valance bond theory

Valence Bond Theory Valence bond theory was proposed by Heitler and London in 1927 based on atomic orbitals and their configuration. According to valence bond theory: A covalent bond is formed when pure, valence atomic orbital of one atom overlaps with another pure, valence atomic orbital of another atom. During covalent bond formation energy releases that means stability increases. each of the overlapping orbitals contains the unpaired electron of opposite spin.The electron pair is shared by both the atoms. The strongest bond is formed when the orbitals of the two atoms overlap to the maximum extent. based on the overlapping of orbitals, two types of covalent bonds are formed. These are known as sigma and pi bonds. Sigma bonds are formed by the end-to-end overlap of atomic orbitals along the inter-nuclear axis known as a head-on or axial overlap. Types of orbital overlap :- Depending upon the type of overlapping, the covalent bonds are of two types, known as sigma (σ ) and pi (π) bond

Heisenberg's Uncertainty Principle

Introduction Werner   Heisenberg   a German physicist  in 1927 stated uncertainty principle which is the consequence of dual behaviour of matter and radiation. It states that it is impossible to determine simulataneously, the exact position and exact momentum( or velocity) of an electron. Heisenberg's Uncertainty Principle states that there is inherent uncertainty in the act of measuring a variable of a particle. Commonly applied to the position and momentum of a particle, the principle states that the more precisely the position is known the more uncertain.  the momentum is and vice versa. This is contrary to classical Newtonian physics which holds all   variables of particles to be   measurable to an arbitrary uncertainty given good enough equipment. The Heisenberg Uncertainty Principle is a fundamental theory in quantum mechanics that defines why a scientist cannot measure multiple quantum variables simultaneously. Until the dawn of quantum mechanics, it was held as a fact that

Structure of atom (part 2)

BOHR'S   MODEL              OF   ATOM   The Bohr's model of the atom was proposed by Neil Bohr in 1915. It came into existence with the modification of Rutherford's model of atom . And it is called morden model of the atom it is based on quantum mechanics. The Bohr's model contains some errors ,but it is important because it describes most of the accepted features of atomic theory without all of the high level math of the morden version . The Bohr  explained that a nucleus (positively charged) is sorrunded by (negatively charged) electrons . Main points of the Bohr's model :-  1. Electron orbit the nucleus in orbits that have a set size and energy . 2.   The energy of the orbit is related to its size the lowest energy is found in the smallest orbit . 3.   Radiation is absorbed and emitted  when electron moves  from one orbit to another .  4. The  Bohr model is a planetary model  (simillar to the planets orbiting the sun ).    Two developments played a m