## Heisenberg’s uncertainty Principle

– Heisenberg’s uncertainty Principle: As it is impossible to know the position and the velocity of any one electron on account of its small size, the best we can do is to speak of the probability or relative chance of finding an electron with a probable velocity. Heisenberg’s Uncertainty Principle …

## MCQ: Structure of atom – Classical Mechanics

1. In the spectrum of hydrogen atom, the series which falls in ultraviolet region is_______ (a) Lyman series (b) Balmer series (c) Paschen series (d) Brackett series Answer. (a) 2. The e/m value for the particles constituting cathode rays is the same regardless of_______ (a) the gas present in cathode …

## De Broglie Equation – The Wave Nature of Electron

De Broglie Equation – de Broglie had arrived at his hypothesis (de Broglie equation) with the help of Planck’s Quantum Theory and Einstein’s Theory of Relativity. – He derived a relationship between the magnitude of the wavelength associated with the mass (m) of a moving body and its velocity. – …

## Zeeman Effect

Zeeman Effect – In 1896 Zeeman discovered that spectral lines are split up into components when the source emitting lines is placed in a strong magnetic field. It is called the Zeeman effect after the name of the discoverer. – The apparatus used to observe the Zeeman effect is shown …

## Bohr-Bury Scheme – Electron arrangement in the orbits

– The Bohr-Bury scheme considers that the maximum number of electrons that each orbit can contain is 2 × n2, where n is the number of orbits. – Having known that planetary electrons numerically equal to the atomic number are revolving about the atomic nucleus in closed orbits, the question …

## Bohr Model of atom – Bohr Theory

– Bohr theory was based on Planck’s quantum theory and was built on some postulates. – Rutherford’s nuclear model simply stated that atom had a nucleus and the negative electrons were present outside the nucleus. – It did not say anything as to how and where those electrons were arranged. …

## Photoelectric Effect and Compton Effect

– In this subject, we will discuss the Photoelectric Effect and Compton Effect Photoelectric Effect – When a beam of light of sufficiently high frequency is allowed to strike a metal surface in a vacuum, electrons are ejected from the metal surface. – This phenomenon is known as the Photoelectric …

## Atomic Spectrum of Hydrogen

– In this subject, we will discuss the atomic Spectrum of Hydrogen Atomic Spectrum – When an element in the vapour or the gaseous state is heated in a flame or a discharge tube, the atoms are excited (energised) and emit light radiations of a characteristic colour. – The colour …

## Atomic Number and Mass Number

– In this subject, we will discuss the Atomic Number and Mass Number Mosley’s Determination of Atomic Number – The discovery that an atom has a nucleus that carries a positive charge raised the question: What is the magnitude of the positive charge? – This question was answered by Henry …

## Rutherford’s Atomic Model (Experiment, Postulates, weakness)

– In this subject, we will discuss the Rutherford’s Atomic Model (Experiment, Postulates, weakness) Alpha particles – Alpha particles are shot out from radioactive elements with very high speed. – For example, they come from radium atoms at a speed of 1.5 × 107m/sec. – Rutherford identified them to be …

## Subatomic Particles: Electrons, Protons, and Neutrons

– In this subject, we will discuss the Subatomic Particles: Electrons, Protons, and Neutrons Subatomic Particles – We have hitherto studied the properties of the three principal fundamental particles of the atom, namely the electron, proton, and neutron. – These are summarised in this Table:   – Nearly all of …

## Electron: Discovery, Charge, Mass, Definition

Cathode Rays – The discovery of electron – The knowledge about the electron was derived as a result of the study of the electric discharge in the discharge tube (J.J. Thomson, 1896). (1) The discharge tube consists of a glass tube with metal electrodes fused in the walls. (2) Through …

## Cyclohexane: Axial and Equatorial Bonds in Cyclohexane

– In this subject, we will discuss the Substituted Cyclohexane: Axial and Equatorial Hydrogen Groups Substituted Cyclohexane: Axial and Equatorial Hydrogen Groups – The six-membered ring is the most common ring found among nature’s organic molecules. – For this reason, we shall give it special attention. – We have already …

## Conformations of Cyclohexane: The Chair and the Boat

– In this subject, we will discuss Conformations of Cyclohexane: The Chair and the Boat Conformations of Cyclohexane: The Chair and the Boat Cyclohexane is more stable than the other cycloalkanes we have discussed, and it has several conformations that are important for us to consider. (1) The most stable conformation …

## Acidity of Carboxylic Acids and Alcohols

– In this subject, we will discuss the Acidity Differences between Alcohols and Carboxylic Acids Acidity of Carboxylic Acids and Alcohols – Carboxylic acids are weak acids, typically having pKa values in the range of 3–5. – Alcohols, by comparison, have pKa values in the range of 15–18 and essentially do …

## The Kinetic Molecular Theory of Gases

– In this subject, we will discuss the Kinetic Molecular Theory of Gases. Introduction to The Kinetic Molecular Theory – The gas laws help us to predict the behavior of gases, but they do not explain what happens at the molecular level to cause the changes we observe in the …

## Acid and Base Dissociation Constants (Ka and Kb)

– In this subject, we will discuss the Acid and Base Dissociation Constants (Ka and Kb) Acid and Base Dissociation Constants – When a weak acid or a weak base is dissolved in water, partial dissociation occurs. – Thus, for nitrous acid, we can write: – where Ka is the …

## Solved problems: Dalton’s Law of Partial Pressures

– Before you solve these problems, you can read this subject for Dalton’s Law of Partial Pressures (Statement, Mathematical, Importance, Application). – Let us understand Dalton’s law by solving these problems. Solved Problems on Dalton’s Law  Problem (1) on Dalton’s Law A mixture of oxygen and neon contains oxygen at …