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प्रश्न
Which group of elements could be placed in Mendeleev's periodic table later on, without disturbing the order? Give reason.
उत्तर
Noble gases are the group of elements which could be placed in Mendeleev's periodic table later on, without disturbing the order. This is because they are inert (unreactive) elements, as their valence shells are completely filled with electrons. Therefore, Mendeleev decided to include these elements in a separate group.
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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 fluorine have in common?
Name two elements whose properties were predicted on the basis fo their positions in Mendeleev's periodic table.
In Mendeleev's periodic table, gap was not left for one of the following elements. This element is:
(a) gallium
(b) beryllium
(c) germanium
(d) scandium
The correct formula of the oxide of Eka-aluminium element predicted by Mendeleev was:
(a) EaO3
(b) Ea3O2
(c) Ea2O3
(d) EaO
State the merits of Mendeleev's classification of elements.
The elements from the zero group are called _______.
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 |
Which one of the following does not increase while moving down the group of the periodic table?
Match the column:
| Column ‘A’ | Column ‘B’ |
| Alkali metals | (a) Group 18 |
| Halogens | (b) Group 1 |
| Noble gases | (c) Group 17 |
