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प्रश्न
Compare and contrast the arrangement of elements in Mendeleev’s periodic Table and the Modern Periodic Table.
उत्तर
| Mendeleev’s periodic table | Modern periodic table |
| Elements are arranged in the increasing order of their atomic masses. | Elements are arranged in the increasing order of their atomic numbers. |
| There are 8 Groups. | There are 18 Groups. |
| Each groups are subdivided into sub group ‘a’ and ‘b’ |
Groups are not subdivided into sub-groups.
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Groups for Noble gas was not present as noble gases were not discovered by that time.
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A seprate group is meant for noble gases.
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There was no place for isotopes.
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This problem has been rectified as slots are determined according to atomic number.
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संबंधित प्रश्न
The three elements having chemical symbols of Si, B and Ge are:
(a) all metals
(b) all non-metals
(c) all metalloids
(d) Si is metalloid, B is metal and Ge is non-metal
What is a period in a periodic table?
Explain why, the first period of the periodic table has only two elements whereas second period has eight elements
Name the metals in the first twenty elements.
Write a short note.
Position of isotopes in the Mendeleev’s and the modern periodic table.
What would be the correct order if Zn, Fe, Al and Cu are arranged in increasing order of reactivity?
In the modern periodic table, the positions of 1 to 20 elements are shown here. Identify the elements A and B. Write their atomic number.
Noble gases belong to______ group of the periodic table.
Compare the radii of two species X and Y. Give reasons for your answer.
- X has 12 protons and 12 electrons
- Y has 12 protons and 10 electrons
Choose an element from period 3 of modern periodic table that matches the description given below in instance. Give a reason for your choice.
It has a similar structure to diamond.
