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The Fundamental Unit of Life
Describe the essential properties of the atomic nucleus. Compare these with the properties of the electron.
The nucleus is a heavily charged positive centre located in a very small space of around 10-15 m. An electron is a very small negatively charged particle with well established charge to mass ratio. The charge on electron forms the smallest unit of charge on atomic particles.
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What are the limitations of Rutherford model of the atom?
Describe Bohr's model of the atom ?
Compare all the proposed models of an atom given in this chapter.
Summarize the rules for writing of distribution of electrons in various shells for the first eighteen elements.
Define valency by taking examples of silicon and oxygen.
Explain with examples, (i) Atomic number, (ii) Mass number, (iii) Isotopes, and (iv) Isobars. Give any two uses of isotopes also.
Na+ has completely filled K and L-shells. Explain.
If Z = 3, what would be the valency of the element? Also, name the element.
Composition of the nuclei of two atomic species X and Y are given as under
X Y
Protons = 6 6
Neutrons= 6 6
Give the mass numbers of X and Y. What is the relation between the two species?
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