Class 10 Periodic Classification of Elements Important Questions

Important Questions Notes Previous Years Questions

Periodic Classification of Elements Important Questions

1. “Atomic number of an element is considered to be a more appropriate parameter than its atomic mass for a chemist.” Take the example of element X (atomic number 13) to justify this statement.
2. How many triads did Dobereiner identify from the existing elements during his time ? Give an example of Dobereiner’s triads.
3. .
   1. The modern periodic table has been evolved through the early attempts of Dobereiner, Newland and Mendeleev. List one advantage and one limitation of all three attempts.
   2. Name the scientist who first of all showed that atomic number of an element is a more fundamental property than its atomic mass.
   3. State modern periodic law.
4. .
   1. How is possible valency of an element determined from the electronic configuration of its atom?
   2. Determine the valency of an element X whose atomic number is 15.
5. How many groups and periods are there in the modern periodic table? How do the atomic size and metallic character of elements vary as we move:
   1. down a group and
   2. from left to right in a period.
6. Given below are some elements of the modern periodic table:
   4Be, 9F, 14Si, 19K, 20Ca
   1. Select the element that has one electron in the outer most shell and write its electronic configuration.
   2. Select two elements that belong to the same group. Give reason for your answer.
   3. Select two elements that belong to the same period. Which one of the two has bigger atomic size?
7. .
   1. Consider the following elements:
      Na(11), Al(13), Cl(17), K(19)
      For the given elements, find out
      (i) valency (ii) period number (iii) group number
   2. An element X belongs to group 17 and element Y belongs to group 1. What type of bond will they form ?
8. Write the achievements and limitations of Mendleev’s periodic table.
9. An element ‘X’ belongs to 3rd period and group 17 of the periodic table.
   1. Identity the element.
   2. Write its electronic configuration and valency.
10. .
    1. How many periods are there in the Modern Periodic Table of elements?
    2. How do atomic radius, valency and metallic character vary down a group?
    3. How do the atomic size and metallic character of elements vary as we move from left to right in a period?