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The Fundamental Unit of Life
If number of electrons in an atom is 8 and number of protons is also 8, then
(i) What is the atomic number of the atom ?
(ii) What is the charge on the atom?
(i) Atomic number defined as the number of protons present in nucleus. Also, number of protons are always equal to number of electron. Thus atomic number of atom is 8.
(ii)Since, there is no gain or loss of electron in atom. Therefore charge on the atom = 0.
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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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