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प्रश्न
The number of periods and groups in the periodic table are ______
विकल्प
6, 16
7, 17
8, 18
7, 18
उत्तर
The number of periods and groups in the periodic table is 7, 18.
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संबंधित प्रश्न
As element X has mass number 40 and contains 21 neutrons in its atom. To which group of the periodic table does it belong?
A metal X is in the first group of the periodic table. What will be the formula of its oxide?
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.
(a) How is possible valency of an element determined from the electronic configuration of its atom ?
(b) Determine the valency of an element X whose atomic number is 15.
What was the basis of the earliest attempts made for classification and grouping of elements?
Why was this basis of classification discarded for future classification of elements?
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?
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
Complete the following triads by inserting the missing elements.
Li, ______, K
Complete the following triads by inserting the missing elements.
Ca, ______, Ba
