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प्रश्न
State the merits of Mendeleev's classification of elements.
उत्तर
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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संबंधित प्रश्न
An atom has electronic configurations 2, 8, 7.
What is the atomic number of this element?
Name two elements whose properties were predicted on the basis fo their positions in Mendeleev's periodic table.
In Mendeleev's periodic table, why was there no mention of noble gases like helium, neon and argon?
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
According to Mendeleev's periodic law, the elements were arranged in the periodic table in the order of: ______
In Mendeleev's periodic table, gaps were left for the elements to be discovered later on. An element which found a vacant place in the periodic table later on is:
(a) Be
(b) Si
(c) Ge
(d) Se
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 : _______
Find the odd one out and give its explanation.
