class 9 chemistry practice Questions

Science 

Date :- 27/01/2023: 


Atomic Structure 


  • Short & very short answer type Questions. 
  1.  Write the names of three elementary particles which constitute an atom.
  2.  Which is heavier, neutron or proton?
  3. How many times a proton is heavier than an electron?
  4.  Give the number of protons in 17Cl35
  5.  What are Isobars? give any two examples
  6.  Name the particle which determines the mass of an atom.
  7.  What type of charge is present in the nucleus of an atom?
  8.  What was the model of an atom proposed by Thomson?
  9. How many elections at the maximum can be present in the first shell?
  10.  Name the Scientist & his experiment to prove that the nucleus of an atom is positively charged.
  11. Define the following terms :(a) Atomic Number and (b) mass number.
  12. Write the charge on sub-atomic particles.
  13.  What are valence electrons? Give examples.
  14.  Symbol 16 S 32 states that-(1) the Atomic number of sulphur. (2) electronic Configuration of Sulphur (3) Mass number of sulphur. (4) Valency of sulphur (5) No. of neutrons.
  15.  Why does helium have Zero valencies?
  16. An atom has the atomic number 21. What would be its configuration?
  17.  What is the octet rule? How do elements reach an octet
  18.  How many electrons M-shell can accommodate?
  19.  If an atom completes K-shell & L-shell. What would be its atomic number?
  20. Why atoms of isotopes are chemically the same?
  21.  Give the representation of three isotopes of Carbon which are C-12, C-13 & C-14.
  22. Write the difference between isotopes and isobars.
  23. Which energy shell has higher energy L-shell or N-shell?
  24. Which energy shell is the nearest to the nucleus of an atom?
  25. What happens when an electron jumps from Lower to a Higher energy level?
  26. What are Neutrons? Explain with an example.
  27. Give the actual mass of the electron & proton in Kg?
  28. Why the relative mass of an electron is taken as Negligible?
  29. Who discovered the Nucleus of the atom?
  30. What is the charge on the alpha particle?
  31. What are canal rays?
  32. How are isotopes of Hydrogen represented?
  33. Write the complete symbol for the atom with the given number [Z] & Atomic mass number (i)               Z = 17, A = 15 (ii) Z = 4, A = 9  (iii) Z = 92, A = 233
  34. What would be an electronic configuration of Na+, Al3+, O2-, Cl- ?
  35. The atom contains 23 protons, 23 electrons, and 25 Neutrons. Find it (i) atomic number (ii) mass number (iii) valence electrons (iv) valency (v) element name
  36. What are isotones? Explain with examples.
  37.     Fill in the Blanks. i.                    -------------- is used as a nuclear fuel. ii.                 Tritium is the isotope of …………….iii.                The size of nucleus ___________  is very small as compared to the size of atom_________iv.                isotope of___________ is used in the treatment of cancer
  38. what are isotones?

     

  39. what are isoelectronic?

  40.  why are orbits called stationary orbits?
  41.  case study-based questions.  during Diwali, most of the children burst into crackers. This generates a lot of air and noise pollution. Asthma patient suffers a lot during this festival. so many people get hurt because of the mishandling of the crackers. Some poisonous gases like Sulphur dioxide and Phosphorus also formed get mixed into the environment. (a)  why should we restrict children to burst crackers? (b) Name the elements which are present in gunpowder that is used in crackers? (c) why we should avoid wearing synthetic clothes during bursting crackers.
  42.   two elements X and Y combine in the ratio of 3: 8 by mass and the compound Z is formed. Z  is one of the essential components of photosynthesis to take place. If  Z is also one of the greenhouse gases. (a)  identify x, y and z.(b)write the electronic configuration of X and Y.(c)  write the atomicity of the molecule Z.
  43. if the symbolic representation of an atom is 3X6. find its valency name and also give the reason for the valency?
  44. sulphur dioxide is colourless pungent-smelling gas and is a measured air pollutant. (a)  write the electronic configuration of its constituent Sulphur and oxygen. (b) write the valency of Sulphur and oxygen. (c)  are Sulphur and oxygen isotopes of the same element? explain your answer.
  45. write the drawbacks of Rutherford's Model of an atom?
  46. (i)  what do you mean by Valence Electrons. (ii) write the electronic configuration of elements S and K.(iii)             write the number of valence electrons in each of these elements.
  47. why is the atomic mass of chlorine taken as 35.5 units and not a whole number like 35 units or 36 units?
  48. what is the maximum number of electrons that can be accommodated in the outermost shell of an atom?


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