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प्रश्न
Rewrite the following statement after correction, if necessary:
Periods are the horizontal rows of elements.
उत्तर
The statement is correct.
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संबंधित प्रश्न
An element X from group 2 of the periodic table reacts with an element Y from group 17 to form a compound.
(a) What is the nature of the compound formed?
(b) State whether the compound formed will conduct electricity or not.
(c) Give the formula of the compound formed.
(d) What is the valency of element X?
(e) How many electrons are there in the outermost shell of an atom of element Y?
The following diagram shows a part of the periodic table containing first three periods in which five elements have been represented by the letters a, b, c, d and e (which are not their chemical symbols):
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1 18 a 2 13 14 15 16 17 b c d e
(i) Select the letter which represents an alkali metal.
(ii) Select the letter which represents a nobles gas.
(iii) Select the letter which represents a halogen.
(iv) What type of bond is formed between a and e?
(v) What type of bond is formed between d and e?
Write the names and symbols of two very reactive metals belonging to group 1 of the periodic table. Explain by drawing electronic structure, how either one of the two metals reacts with a halogen. With which name is the bond formed between these elements known and what is the class of the compound so formed known? State any four physical properties of such compounds.
The non-metal A is an important constituent of our food and most of the fuels around us. A forms two oxides B and C. The oxide B is poisonous whereas oxide C causes global warming.
(a) Identify A, B and C.
(b) To which group of periodic table does A belong?
(c) Name another element which is placed in the same group as A.
The basis of the classifications proposed by Dobereiner, Newlands and Mendeleev was ______.
Moseley’s periodic table is based on atomic mass.
Consider the following elements 20Ca, 8Or 18Ar, 16S, 4Be, 2He
Which of the above elements would you expect to be in group 16 of the Periodic Table?
The atom of an element has electronic configuration 2, 8, 7. To which of the following elements would it be chemically similar?
Complete the following triads by inserting the missing elements.
Li, ______, K
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.
