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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
An element X from group 2 reacts with element Y from group 16 of the periodic table.
(a) What is the formula of the compound formed?
(b) What is the nature of bond in the compound formed?
Atoms of eight elements A, B, C, D, E, F, G and H have the same number of electron shells but different number of electrons in their outermost shells. It was found that elements A and G combine to form an ionic compound. This ionic compound is added in a small amount to almost all vegetables and dishes during cooking. Oxides of elements A and B are basis in nature while those of elements E and F acidic. The oxide of element D is, however, almost neutral. Based on the above information, answer the following questions:
(a) To which group or period of the periodic table do these elements belong?
(b) What would be the nature of compound formed by a combination of elements B and F?
(c) Which two of these elements could definitely be metals?
(d) Which one of the eight elements is most likely to be found in gaseous state at room temperature?
(e) If the number of electrons in the outermost shell of elements C and G be 3 and 7 respectively, write formula of the compound formed by the combination of C and G.
The molecular formula of the chloride of element X is XCl. This compound is a solid having a high melting point. Which of the following elements be present in the same group as X.
Answer the following question.
Write the name, symbol, and electronic configuration of an element X whose atomic number is 11.
An element X combines with oxygen to form an oxide XO. This oxide is electrically conducting. Write the formula of the compound formed when X reacts with chlorine.
The atom of an element has electronic configuration 2, 8, 7. To which of the following elements would it be chemically similar?
Which one of the following does not increase while moving down the group of the periodic table?
Arrange the following elements in the order of their decreasing metallic character
Na, Si, Cl, Mg, Al
An element X of group 15 exists as diatomic molecule and combines with hydrogen at 773 K in presence of the catalyst to form a compound, ammonia which has a characteristic pungent smell.
- Identify the element X. How many valence electrons does it have?
- Draw the electron dot structure of the diatomic molecule of X. What type of bond is formed in it?
- Draw the electron dot structure for ammonia and what type of bond is formed in it?
Justify. Element 'X' forms an oxide with the formula X2O3 which is a solid with a high melting point. ‘X’ would most likely be placed in the group of the Periodic Table as Al.
