Physical Chemistry

  Radioactivity ** A number of elements such as uranium and radium are unstable. Their atomic nucleus breaks of its own accord to form a smaller atomic nucleus of another element. The protons and neutrons in the unstable nucleus regroup to give the new nucleus. This causes the release of excess …

Rate of radioactive decay  ** The decay of a radioactive isotope takes place by disintegration of the atomic nucleus. It is not influenced by any external conditions. Therefore the rate of decay is characteristic of an isotope and depends only on the number of atoms present. ** If N be …

Radioactivity   ** A number of elements such as uranium and radium are unstable. Their atomic nucleus breaks of its own accord to form a smaller atomic nucleus of another element. The protons and neutrons in the unstable nucleus regroup to give the new nucleus. This causes the release of excess …

Types of Radioactive decay ** According to the theory put forward by Rutherford and Soddy (1903), radioactivity is a nuclear property.  ** The nucleus of a radioactive atom is unstable. It undergoes decay or disintegration by spontaneous emission of an α– or β-particle. ** This results in the change of …

    The radioactive radiation can be detected and measured by a number of methods. The important ones used in modern practice are listed below. (1) Cloud Chamber   ** This technique is used for detecting radioactivity. ** The chamber contains air saturated with water vapour. ** When the piston …

  Nuclear reaction   ** A nuclear reaction is different from a chemical reaction. ** In a chemical reaction, atoms of the reactants combine by a rearrangement of extranuclear electrons but the nuclei of the atoms remain unchanged. ** In a nuclear reaction, on the other hand, it is the …

    1. The atoms of an element which have the same number of protons and different number of neutrons are called_______ (a) isotopes (b) isobars (c) isotones (d) isomers Answer. (a)    2. Isotopes of an element have _______ atomic number but _______ mass numbers. (a) same, same (b) different, same …

    In this lesson , the Difference between Isotopes, Isobar and Isotones will be discussed with some Common Examples for all types. What are Isotopes? Isotopes may be defined as:   (1) The atoms of an element which have the same number of protons and different number of neutrons …

  Definition of isotopes Isotopes may be defined as :   (1) The atoms of an element which have the same number of protons and different number of neutrons are called Isotopes. (2) The atoms of an element which have the same atomic number but different atomic masses or mass numbers. Examples …

  Definition of isotopes Isotopes may be defined as :   (1) The atoms of an element which have the same number of protons and different number of neutrons are called Isotopes. (2) The atoms of an element which have the same atomic number but different atomic masses or mass numbers. …

  Separation of Isotopes Since isotopes have exactly similar chemical properties, their separation by chemical means is out of question. Their difference in those physical properties which depend on the mass of the atom has been utilised to effect their separation. The methods commonly employed for the purpose are: (1) Gaseous Diffusion …

  Identification of Isotopes ** The positive rays produced in a discharge tube consist of nuclei of atoms. ** The deflection of positive rays in an electric and magnetic field is proportional to e/m, the charge on the particle divided by its mass.   ** The nuclei obtained from an …

  What are Isotopes? ** Contrary to Dalton’s Atomic theory, all atoms of a given element are not necessarily identical. In fact, most elements have been shown to be composed of two or more types of atoms mixed in a fixed proportion. ** The different atoms of such an element …

  Work ** Work in thermodynamics is defined as in classical mechanics. ** When part of the surroundings exerts a macroscopically measurable force F on matter in the system while this matter moves a distance dx at the point of application of F, then the surroundings has done work on the system:   …

  Introduction ** Thermodynamics is based on a few statements called laws that have broad application to physical and chemical systems. ** As simple as these laws are, it took many years of observation and experimentation before they were formulated and recognized as scientific laws.   ** Three such statements …

  What is the System and  Surroundings ? ** Imagine you have a container holding some material of interest to you, as in Figure  blow. ** The container does a good job of separating the material from everything else.   ** Imagine, too, that you want to make measurements of …