Rutherford model It is a conceptual model for the structure of the atom formulated by the scientist Ernest Rutherford, after his assistant Hans Jaeger commissioned Inst Marsden in 1909 to conduct the famous gold foil experiment at the University of Manchester, then Rutherford conducted analytical studies of the results of the experiment and then published his model for the structure of the atom in the year 1911, which proved the world There is an error in Joseph John Thomson’s so-called Thomson model of the atom. Rutherford’s new model of the atom indicated,^[1] Based on experimental results, there is a relatively strong central charge concentrated in a small volume compared to the rest of the atom, and this center contains most of the mass of the atom. This region was later called the nucleus.

empirical basis for the model[عدل]

Rutherford disproved Thomson’s model in 1911 with his famous experiment, known as Rutherford’s experiment, in which he proved that an atom had a small, heavy nucleus. Rutherford designed an experiment to use alpha particles emitted by a radioactive element as probes to the invisible world of atomic structure. If Thomson was correct, the beam would go straight through the gold foil, but most of the beams went through the foil while some were reflected.^[2]

As an explanation for the unexpected experimental results, Rutherford offered his own physical model of sub-atomic particles. In this model, the atom consists of a central charge and is now known as the nucleus of the atom, although Rutherford did not use the term “nucleus” in his paper. He also assumed that this central charge was surrounded by a cloud of electrons that he assumed revolved around it. In this May 1911 paper, Rutherford himself committed the existence of a small central region of very high positive charge in an atom.^[3]

To get a tangible result, Rutherford considered a high-speed alpha particle passing through an atom that had a positive central charge, surrounded by a compensating negative charge of electrons.^[4]

Taking purely biological considerations of how far particles of known velocity could penetrate toward a central charge of 100 units, Rutherford was able to calculate the radius of the charge of the gold foil, which he assumed should be no less than 3.4 x 10⁻¹⁴ meter. It was in a golden atom with a diameter of 10⁻¹⁰ meters – a very surprising result, since it involves the passage of a strong central charge less than 1/3000th the diameter of an atom.^[5][6]

Rutherford’s model concentrated a great deal of the atom’s charge and mass into a very small fraction, but took no account of the remaining electrons or remaining atomic mass. Rutherford also derived from Hantaro Nagaoka’s atomic model in which electrons are arranged in one or more rings, with a definite structure of fixed rings. Thomson’s model of the atom also postulated that there were rings of electrons orbiting around it. It was claimed by Jean-Baptiste Perrin in his Nobel Lecture^[7] He was the first to propose this model in his paper dated 1901.

Rutherford’s paper suggested that the central charge of an atom might be proportional to its atomic mass in hydrogen. For gold, the atomic mass of gold was estimated at 197 as it had not been calculated with great accuracy until that time, and thus Rutherford assumed it was probably 196. However, Rutherford did not attempt a direct estimate of the central charge in relation to the atomic number, since the atomic number of gold at that time was only Just a number in the table, but he put an approximation of that shipment to be over 100 units. Rutherford had already proposed that value as 98 units of positive charge, half of 196. Thus, Rutherford did not formally suggest that the number, periodic table position 79, and atomic mass 98 or 100 be the same.^[8]

A month after Rutherford’s paper appeared, the proposal regarding the exact identity of atomic number and atomic charge was made by Antonius van den Broeck, and then confirmed, within two years, by Henry Moseley.

Rutherford’s model can be summarized as follows:^[9]

• The electron cloud of the atoms, i.e. the atomic orbital, does not affect alpha particle scattering.
• Much of the positive charge of an atom is concentrated in a relatively small volume in the center of the atom, known today as the atomic nucleus. The magnitude of this charge is proportional to the atomic mass. It is now known that the remaining mass is mostly attributed to neutrons. This central mass is responsible for scattering both alpha and beta particles.
• The mass of heavy atoms such as gold is mostly concentrated in the central charge region, where calculations show that they are not deflected or moved by high-speed alpha particles, which have very high momentum compared to electrons, but not with respect to the mass of the heavy atom as a whole.
• The diameter of an atom itself is about 100,000 (10⁵) times the diameter of the nucleus.^[10] This can be likened to placing a grain of sand in the middle of a football field.^[7]

Paradigm’s contribution to modern science[عدل]

After Rutherford’s discovery, scientists began to realize that the atom is not, after all, a single particle, but is made up of much smaller particles. Subsequent research determined the exact atomic structure that led to Rutherford’s gold foil experiment. Scientists eventually discovered that atoms have a positively charged nucleus, with an exact atomic number of charges in the center, with a radius of about 1.2 x 10⁻¹⁵ متر× [عدد الكتلة الذرية]¹⁄₃. It was also discovered later that the electrons are much smaller than that.

Later scientists using X-rays found that the expected number of electrons is the same as the atomic number in an atom. When X-rays pass through an atom, some of it is scattered while the rest passes through the atom. Since X-rays lose intensity primarily due to scattering in electrons, by observing the rate of decrease in X-ray intensity, the number of electrons in an atom can be accurately estimated.

Avatar[عدل]

See also Bohr’s model which also applies to the section below.

Rutherford’s model established the idea that there are many electrons in rings around the nucleus, as postulated by the Nagawaka model. However, once Niels Bohr modified this view into a picture of a few planet-like electrons for light atoms, the Rutherford-Bohr model captured the public imagination. Since then, the form has been used as a symbol for atoms and even for atomic energy, although the term nuclear energy is more appropriate. Examples of its use over the past century include but are not limited to:

• The logo of the United States Atomic Energy Agency, which was partly responsible for its later use in connection with nuclear fission technology in particular.
• The flag of the International Atomic Energy Agency is a Rutherford atom surrounded by olive branches.
• The logo of the United States Baseball League is Rutherford’s pattern of an atom.
• A similar symbol, the atomic vortex, was chosen as the symbol of the American Atheist League, and has come to be used as a symbol for atheism in general.
• Unicode variant code uses U + 269B (⚛) inspired by Rutherford’s model.
• The Rutherford Model symbol is often used on maps to indicate the presence of facilities related to nuclear energy.

Reference[عدل]

• Chemistry portal
• Quantum Mechanics Portal
• Physics portal
• Physical chemistry portal

Rutherford’s model of the atom On sister projects:
	Pictures and audio from Commons.

Retrieved from «https://en.wikipedia.org/w/index.php?title=Rutherford’s model of the atom&oldid=60024615»