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प्रश्न
What is the need for classification of elements?
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उत्तर
It is impossible for a chemist to study all the elements and their compounds. Hence, classification is a must.
Following are the reasons for the classification of elements:
- To study elements better
- To correlate the properties of the elements with some fundamental properties which are characteristic of all the elements
- To reveal relationships between elements
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संबंधित प्रश्न
Write the electronic configuration of two elements X and Y whose atomic numbers are 20 and 17 respectively. Write the molecular formula of the compound formed when element X reacts with element Y. Draw the electron-dot structure of the product and also state the nature of the bond formed between both the elements.
An element A has an atomic number of 6. Another element B has 17 electrons in its one neutral atom.
(a) In which groups of the periodic table would you expect to find these elements?
(b) what type of bond is formed between A and B?
(c) Suggest a formula of the compound formed between A and B.
A metal X is in the first group of the periodic table. What will be the formula of its oxide?
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.
Two elements X and Y belong to group 1 and 2 respectively in the same period of periodic table. Compare them with respect to:
(i) the number of valence electrons in their atoms
(ii) their valencies
(iii) metallic character
(iv) the sizes of their atoms
(v) the formulae of their oxides
(vi) the formulae of their chlorides
Alkaline earth metals have valency 2. This means that their position in the modern periodic table is in ______.
In which block of the modern periodic table are the nonmetals found?
The number of periods and groups in the periodic table are ______
Which one of the following statements is not correct about the trends in the properties of the elements of a group on going down in a group?
The atom of an element has electronic configuration 2, 8, 7. To which of the following elements would it be chemically similar?
