Rutherford's Model Of The Atom
On the basis of alpha particle scattering experiment, Rutherford gave a nuclear model of the atom.Rutherford's model of atom (or structure of atom) can be described as follows :
1.An atom consists of a positively charged, dense and very small nucleus containing all the protons and neutrons (protons have positive charge whereas neutrons have no charge). Almost the entire mass of an atom is concentrated in the nucleus.
2.The nucleus is surrounded by negatively charged electrons. The electrons are revolving round the nucleus in circular paths at very high speeds. The circular paths of the electrons are called orbits.
3.The electrostatic attraction between the positively charged nucleus and negatively charged electrons holds the atom together.
4.An atom is electrically neutral.This is because the number of protons and electrons in an atom is equal.
5.Most of the atom is empty space.
We will now describe the structures of some atoms on the basis of Rutherford's model of atom.
The simplest atom is that of hydrogen.It contains one proton and one electron. According to Rutherford's theory, a hydrogen atom consists of a small nucleus containing one proton, and one electron revolving around it (Figure 17). The nucleus is almost at the centre of the atom. Since the hydrogen atom contains an equal number of protons and electrons (1 each), it is electrically neutral. Please note that the nucleus of an ordinary hydrogen atom does not contain any neutrons in it.
The next simplest atom is that of helium.A helium atom consists of a small central nucleus containing 2 protons and 2 neutrons, and there are 2 electrons revolving around this nucleus (Figure 18). Since the helium atom contains an equal number of protons and electrons (2 each), therefore, it is electrically neutral.
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Structure of the Atom - Notes
1. Drawback of Rutherford’s Model of the Atom
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2. Rutherford’s Experiment - Discovery of Nucleus
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4. For the symbols H, D and T,tabulate three sub-atomic particles found in each of them.
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9. Structure of The Atom - Study Points
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10. Limitations of Rutherford's model of the atom
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11. Arrangement Of Electrons In The Atoms
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12. All about Names of the Chemical Elements
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17. How to learn naming Chemical Formulae?
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22. Rules for writing of distribution of electrons in various shells for the first 18 elements
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24. Electronic Configurations of First 20 Elements
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25. Comparison between Proton, Neutron and Electron
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33. The Physical Properties of the Isotopes of an Element are Different
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39. All the Isotopes of an Element Have Identical Chemical Properties
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42. Relationship Between Mass Number and Atomic Number
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44. Electronic Configurations of Noble Gases (or Inert Gases)
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50. Applications of Radioactive Isotopes
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