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Question
State the merits of Mendeleev's classification of elements.
Solution
The merits of Mendeleev's classification of elements:
1. Mendeleev's periodic law predicted the existence of certain elements such as gallium, scandium and germanium, which were not discovered at that time.
2. Mendeleev's periodic table could also predict the properties of various elements based on their position in the periodic table.
3. Mendeleev's periodic table could place group 18 elements, called Noble gases in the periodic table, when they were discovered.
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RELATED QUESTIONS
How do the properties of eka-aluminium element predicted by Mendeleev compare with the actual properties of gallium element?
State any three limitations of Mnedeleev's classification of elements.
An element X forms an oxide X2O3. In which group of Mendeleev's periodic table is this element placed?
(a) group II
(b) group III
(c) group V
(d) group VIII
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?
Eka boron : Scandium : : Eka Aluminum : _______
Two elements in the same position : demerit of Newland's octaves : : place for Isotopes : _______
Describe the merits of Mendeleev’s periodic table?
An atom has electronic configurations 2, 8, 7.
To which of the following elements would it be chemically similar? (Atomic numbers are given in parentheses.)
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 |
