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प्रश्न
Mendeleev predicted the existence of certain elements not known at that time and named two of them as eka-aluminium, and eka-silicon.
(a) Name the element which has taken the place of (i) eka-aluminium, and (ii) eka-silicon
(b) Mention the period/periods of these elements in the modern periodic table.
(c) Write the group/ groups of these elements in the modern periodic table.
(d) Classify these elements as metals, non-metals or metalloids.
(e) How many valence electrons are present in the atoms of each of these elements?
उत्तर
(a) (i) Gallium is the element which has taken the place of eka-aluminium.
(ii) Germanium is the element which has taken the place of eka-silicon.
(b) Gallium and Germanium are placed in the 4th period of the periodic table.
(c) Gallium belongs to group 13 and Germanium belongs to group 14 in the periodic table.
(d) Gallium is a metal and Germanium, a metalloid.
(e) Gallium, which belongs to group 13, has 3 valence electrons in its atom, and germanium which belongs to group 14 has 4.
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संबंधित प्रश्न
What property do all elements in the same column of the Periodic Table as boron have in common?
What was the Mendeleev's basis for the classification of elements?
Name two elements whose properties were predicted on the basis fo their positions in Mendeleev's periodic table.
Describe two anomalies of Mendeleev's periodic classification of elements.
What name were given by Mendeleev to the then undiscovered element gallium?
How do the properties of eka-aluminium element predicted by Mendeleev compare with the actual properties of gallium element?
In Mendeleev's periodic table, why was there no mention of noble gases like helium, neon and argon?
The elements from the zero group are called _______.
Eka boron : Scandium : : Eka Aluminum : _______
Match the column:
| Column ‘A’ | Column ‘B’ |
| Alkali metals | (a) Group 18 |
| Halogens | (b) Group 1 |
| Noble gases | (c) Group 17 |
