General awareness: General Science notes # 1

• E.Goldstein discovered the presence of new radiations in a gas discharge and called them canal rays which later led to the discovery of Protons.
• The mass of a proton is taken as one unit and its charge as plus one.
• J.J.Thomson won nobel prize in physics in 1906 for his work on the discovery of electrons.
• The mass of an electron is negligible and its charge is minus one.
• Thomson proposed that  a) An atom consists of a positively charged sphere and the electrons are embedded in it.           b) The atom as a whole is electrically neutral.
• E.Rutherford was known as the father of nuclear physics.
• Rutherford got the nobel prize in chemistry in 1908 for his work on radioactivity and the discovery of the nucleus of an atom with the gold foil experiment.
• Neils Bohr got the nobel prize for his work on the structure of atom in 1928.
• J.Chadwick discovered Neutron.
• Neutron had no charge and a mass nearly equal to that of proton.
• Neutrons are present in the nucleus of all atoms, except hydrogen.
• Atomic number(Z) is defined as the total number of protons present in the nucleus of an atom.
• The mass number is defined as the sum of the total number of protons and neutrons present in the nucleus of an atom.
• Protons and neutrons are called Nucleons.
• Isotopes are defined as the atoms of the same element, having the same atomic number but different mass number.
• Three isotopes of hydrogen atom - Protium, Deuterium and Tritium
• An isotope of Uranium is used as a fuel in nuclear reactor.
• An isotope of Cobalt is used in the treatment of cancer.
• An isotope of iodine is used in the treatment of Goitre.
• Isobars are defined as the atoms of different elements with different atomic numbers which have the same mass number.