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प्रश्न
Find the odd one out and give its explanation.
पर्याय
Gallium
Scandium
Germanium
Calcium
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उत्तर
Calcium
Explanation:
The odd one out is calcium. because Scandium, Gallium, and Germanium were predicted by Mendeleev before their discovery and temporarily named Eka-boron, Eka-aluminium, and Eka-silicon. Calcium, however, was already a known element and was not part of Mendeleev’s predicted blank spaces in the periodic table.
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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 were the criteria used by Mendeleev in creating his Periodic Table?
Why do you think the noble gases are placed in a separate group?
Which of the following statements is not a correct statement about the trends when going from left to right across the periods of periodic Table.
What property do all elements in the same column of the Periodic Table as fluorine have in common?
An atom has electronic configurations 2, 8, 7.
What is the atomic number of this element?
In the classification of the them known elements, Mendeleev was guided by two factors. What are those two factors?
Name two elements whose properties were predicted on the basis fo their positions in Mendeleev's periodic table.
The three elements predicted by Mendeleev from the gaps in his periodic table were known as eka-boron, eka-aluminimum and eka-silicon. What names were given to these elements when they were discovered later on?
Which group of elements could be placed in Mendeleev's periodic table later on, without disturbing the order? Give reason.
State the periodic law on which Mendeleev's periodic table table was based. Why and how was this periodic law changed?
State the merits of Mendeleev's classification of elements.
Describe two anomalies of Mendeleev's periodic classification of elements.
What name were given by Mendeleev to the then undiscovered element scandium.
Why did Mendeleev leave some gaps in his periodic table?
In Mendeleev's periodic table, why was there no mention of noble gases like helium, neon and argon?
State any three limitations of Mnedeleev's classification of elements.
Besides gallium, which two other elements have since been discovered for which Mendeleev had left gaps in his 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
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
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?
State the merits of Mendeleev's classification of elements.
Find the correlation:
Two elements in the same position : demerit of Newland's octaves : : place for Isotopes : ______
Find the odd one out and give its explanation.
Match the columns.
| Column A | Column B |
| 1) Eka-aluminium | a) Scandium |
| 2) Eka-Silicon | b) Gallium |
| 3) Eka-boron | c) Germanium |
| d) Beryllium |
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 |
Write the name.
The family of group 1 elements.
Write the name.
The family of elements having zero valency.
Write a scientific reason.
In a group, the size of the atom increases as it goes down from the top.
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 |
