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The Fundamental Unit of Life
What are the uses of isotopes?
Isotopes have the following uses:
(i) Treatment of diseases—Radioactive isotopes are used for the treatment of dreadful diseases like cancer. Cobalt-60 is used to kill malignant cells in patients suffering from cancer.
(ii) Radioactive isotopes are used in chemical analysis.
(iii) Diseases in plants are investigated by using radioactive isotopes.
(iv) Production of energy : Uranium-235 can be subjected to fission process and thus production of electricity.
(v) Dating of plants, animals/human beings obtained from ancient times after excavation by using carbon-14.
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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?
For the following statements, write T for True and F for False.
(a) J.J. Thomson proposed that the nucleus of an atom contains only nucleons.
(b) A neutron is formed by an electron and a proton combining together. Therefore, it is neutral.
(c) The mass of an electron is about 1/2000 times that of proton.
(d) An isotope of iodine is used for making tincture iodine, which is used as a medicine.
Rutherford’s α-particle scattering experiment was responsible for the discovery of
Isotope of an element has
Number of valence electrons in Cl- ion are
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