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प्रश्न
The basis of the classifications proposed by Dobereiner, Newlands and Mendeleev was ______.
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उत्तर
The basis of the classifications proposed by Dobereiner, Newlands and Mendeleev was atomic masses
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संबंधित प्रश्न
State whether the following statement is true of false:
The elements in a group have consecutive atomic numbers.
An atom has the electron structure of 2, 7.
(a) What is the atomic number of this atom?
(b) To which of the following would it be chemically similar?
7N, 15P, 17Cl, 18Ar
(c) Why would you expect it to be similar?
A non-metal X which is the largest constituent of air combines with hydrogen when heated in the presence of iron as catalyst to form a gas Y. When gas Y is treated with sulphuric acid, it forms a compound Z which is used as a chemical fertiliser.
(a) What are X, Y and Z?
(b) To which group of periodic table does X belong?
(c) Name the periodic table in which X is placed.
(d) Which element is placed just before X in the period?
(e) Which element is placed just after X in the period?
Alkaline earth metals have valency 2. This means that their position in the modern periodic table is in ______.
Give a reason why elements need to be properly classified.
Write the name.
The atom having smallest atomic radius from group 1.
State whether true or false. If false, correct the statement.
Metals can gain electrons.
The number of periods and groups in the periodic table are ______
The elements of group 16 are called ______
Which one of the following does not increase while moving down the group of the periodic table?
