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प्रश्न
Give a reason why elements need to be properly classified.
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उत्तर
Reason of classification of elements:
- It makes the study of elements in an organized manner.
- To help and correlate the properties of elements with the fundamental properties of different states of matter.
- To help to define the relationship of one element with others.
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संबंधित प्रश्न
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?
An element A from group 14 of the periodic table combines with an element B from group 16.
(i) What type of chemical bond is formed?
(ii) Give the formula of the compound formed.
Find the neutral atom in the periodic table which has the same number of electrons as K+ and Cl−. What is this number?
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.
Name the neutral atom in the Periodic Table which has the same number of electrons as K+ and Cl-.
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?
Arrange the following elements in the order of their decreasing metallic character
Na, Si, Cl, Mg, Al
Complete the following cross word puzzle
Across:
(1) An element with atomic number 12.
(3) Metal used in making cans and member of Group 14.
(4) A lustrous non-metal which has 7 electrons in its outermost shell.
Down:
(2) Highly reactive and soft metal which imparts yellow colour when subjected to flame and is kept in kerosene.
(5) The first element of second Period
(6) An element which is used in making fluorescent bulbs and is second member of Group 18 in the Modern Periodic Table
(7) A radioactive element which is the last member of halogen family.
(8) Metal which is an important constituent of steel and forms rust when exposed to moist air.
(9) The first metalloid in Modern Periodic Table whose fibres are used in making bullet-proof vests
Relate the names of the following scientists with the statements given below.
Arranged elements into groups containing three elements each.
Complete the following triads by inserting the missing elements.
Li, ______, K
