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प्रश्न
Why did Mendeleev leave some gaps in his periodic table?
उत्तर
Mendeleev left some gaps in his periodic table for the elements which were not known at that time, to ascertain that elements having the same properties fell in the same vertical column or group, without disturbing the arrangement of previous elements.
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संबंधित प्रश्न
Besides gallium, which other elements have since been discovered that were left by Mendeleev in his Periodic Table? (any two)
What property do all elements in the same column of the Periodic Table as boron have in common?
Name two elements whose properties were predicted on the basis fo their positions in Mendeleev's periodic table.
State the merits of Mendeleev's classification of elements.
How do the properties of eka-aluminium element predicted by Mendeleev compare with the actual properties of gallium element?
Which group of elements was missing from Mendeleev's original periodic table?
The correct formula of the oxide of Eka-aluminium element predicted by Mendeleev was:
(a) EaO3
(b) Ea3O2
(c) Ea2O3
(d) EaO
Find the odd one out and give its explanation.
Match the columns.
| Column A | Column B |
| 1) Triads | a) Mendeleev |
| 2) Octave | b) Dobereiner |
| 3) Atomic number | c) Thomson |
| 4) Atomic mass number | d) Moseley |
| e) Newland |
Match the column:
| Column ‘A’ | Column ‘B’ |
| Alkali metals | (a) Group 18 |
| Halogens | (b) Group 1 |
| Noble gases | (c) Group 17 |
