What You Will Learn!
- The students will have a clear vision about the Structure of Atom.
- The students will be able to differentiate between the absorption spectra and emission spectra.
- The students will be able to identify Hydrogen Spectra,
- The learners will know about Aufbau Principle, Hund's rule of Maximum Multiplicity and Electronic Configuration of Elements.
Description
An atom is electrically neutral, and if it contains negatively charged electrons it must also contain
some positively charged particles, and the supposition that they existed within atoms came about
as a result of Rutherford's experiments in which he bombarded elements with the alpha - rays and
alpha - rays were given off by radioactive elements. The neutron was discovered in 1932 by James
Chadwick by bombarding beryllium with alpha rays.
The electron and proton have equal, but opposite, electric charges; the neutron is not charged.
The electron and proton have equal, but opposite, electric charges; the neutron is not charged.
The existence of electrons in atoms was first suggested, by J.J. Thomson, as a result of
experimental work on the conduction of electricity through gases at low pressures, which
produces cathode rays and x-rays, and a study of radioactivity by Becquerel, the Curies and
Rutherford.
Some of the important properties of the cathode rays studied by Sir J.J. Thomson and others are:
Cathode rays come out at right angles to the surface of the cathode and move in straight lines.
Their path is independent on the position of the anode.
They produce phosphorescence on certain salts like ZnS and fluorescence on glass.
They blacken photographic plates.
The rays pass through thin sheet of metals. If the metal sheet is too thick to be penetrated the
rays cast a shadow.
They produce X-ray when they strike a metal.
Who Should Attend!
- Biggane and eleventh standard students.
