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प्रश्न
Write the name.
The family of group 1 elements.
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उत्तर
Alkali metals
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संबंधित प्रश्न
The element eka-silicon in Mendeleev’s periodic table is known as ………… in the modern periodic table.
Besides gallium, which other elements have since been discovered that were left by Mendeleev in his Periodic Table? (any two)
Why do you think the noble gases are placed in a separate group?
What property do all elements in the same column of the Periodic Table as boron have in common?
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?
What was the Mendeleev's basis for the classification of elements?
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 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.
What name were given by Mendeleev to the then undiscovered element gallium?
What name were given by Mendeleev to the then undiscovered element germanium?
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?
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?
Which group of elements was missing from Mendeleev's original periodic table?
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?
Why could no fixed position be given to hydrogen in Mendeleev's periodic table?
State the merits of Mendeleev's classification of elements.
Find the correlation:
Eka boron : Scandium : : Eka Aluminum : ______
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.
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 elements having zero valency.
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 |
