Ernest Rutherford postulated the nuclear structure of the atom, discovered alpha and beta rays, and proposed the laws of radioactive decay. He received the Nobel Prize in Chemistry in 1908.
According to the Rutherford atomic model: The positively charged particles and most of the mass of an atom was concentrated in an extremely small volume. He called this region of the atom as a nucleus. Rutherford model proposed that the negatively charged electrons surround the nucleus of an atom.
The Geiger–Marsden experiments (also called the Rutherford gold foil experiment) were a landmark series of experiments by which scientists discovered
that every atom has a nucleus where all of its positive charge and most of its mass is concentrated., Rutherford was curious. He wondered how he could use alpha particles to learn about the structure of the atom. He decided to aim a beam of alpha particles at a sheet of very thin gold foil. He chose gold because it can be pounded into sheets that are only 0.00004 cm thick.
Rutherford was the first person to knowingly split the nucleus, in 1918 at Manchester University where he bombarded nitrogen with naturally occurring alpha particles from radioactive material and observed a proton emitted with energy higher than the alpha particle.
From the location and number of α-particles reaching the screen, Rutherford concluded the following: i) Almost 99% of the α-particles pass through the gold foil without any deflection. So atom must be having a lot of empty space in it. ii) Several α-particles get deflected at angles.
Rutherford's gold foil experiment showed that the atom is mostly empty space with a tiny, dense, positively-charged nucleus. Based on these results, Rutherford proposed the nuclear model of the atom.
The model described the atom as a tiny, dense, positively charged core called a nucleus, in which nearly all the mass is concentrated, around which the light, negative constituents, called electrons, circulate at some distance, much like planets revolving around the Sun.
To split an atom a neutron, travelling at just the right speed, is shot at the nucleus. Under the right conditions the nucleus splits into two pieces and energy is released. This process is called nuclear fission. This chain reaction very rapidly multiplies the amount of atoms split and the amount of energy released.
The fission process becomes self-sustaining as neutrons produced by the splitting of atom strike nearby nuclei and produce more fission. This is known as a chain reaction and is what causes an atomic explosion.
When an atom is split, three types of radiation that can damage living tissues are released. Alpha particles are made up of protons and neutrons and cannot penetrate human skin, but do damage if released inside a body.
The word proton is Greek for "first", and this name was given to the hydrogen nucleus by Rutherford in 1920. In previous years, Rutherford had discovered that the hydrogen nucleus (known to be the lightest nucleus) could be extracted from the nuclei of nitrogen by atomic collisions.
Rutherford's contribution was the discovery that atoms contain a positively charged nucleus much smaller than the actual atom.
Limitations of Rutherford Model.
This atomic model failed to explain stability of atoms. According to the model, electrons revolve around the positively charged nucleus. It's not possible for a long run as we know atoms are stable while any particle in a circular orbit would undergo acceleration.
Rutherford is known for his pioneering studies of radioactivity and the atom. He discovered that there are two types of radiation, alpha and beta particles, coming from uranium. He found that the atom consists mostly of empty space, with its mass concentrated in a central positively charged nucleus.
The Nobel Prize in Chemistry 1908 was awarded to Ernest Rutherford "for his investigations into the disintegration of the elements, and the chemistry of radioactive substances."
On October 19, 1937, Rutherford died in Cambridge, England at age 66 from the complications of a strangulated hernia.
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