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प्रश्न
What is modern periodic law?
उत्तर
Modern periodic law states that the physical and chemical properties of elements are a periodic function of their atomic numbers i.e., if the elements are arranged in the order of their atomic numbers, the elements with similar properties are repeated after definite regular intervals.
Concept Insight: The elements are characterized by their atomic number as well as atomic weight. Modern periodic law uses atomic number which is number of protons or number of electrons present in an atom of an element.
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संबंधित प्रश्न
Study the following table in which positions of six elements A, B, C, D, E and F are shown as they are in the modern periodic table:
|
Group→
Period↓ |
1
|
2
|
3-12
|
13
|
14
|
15
|
16
|
17
|
18
|
| 2 | A | B | C | ||||||
| 3 | D | E | F |
On the basis of the above table, answer the following questions:-
(i) Name the element which forms only covalent compounds.
(ii) Name the element which is a metal with valency three.
(iii) Name the element which is a non-metal with valency three.
(iv) Out of D and E, which is bigger in size and why?
(v) Write the common name for the family to which the elements C and F belong.
Name the element that has two shells, both of which are completely filled with electrons.
How does the valency of elements vary in going down a group of the periodic table?
State the valency of the elements of periods 3 and write the formula of their oxides.
Write two reasons responsible for late discovery of noble gases ?
Arrange the following as per instruction given in the bracket.
Cl, F, Br, I (increasing electron affinity)
The elements of one short period of the periodic table are given below in order from left to right:
| Li | Be | B | C | O | F | Ne |
Which one of the above elements belongs to the halogen series?
An element belongs to the third period and Group IIIA (13) of the periodic table. State: the name of the element.
The electronic configuration of an element is 2, 8, 4. State it:
group and period in the Modern Periodic Table.
Fill in the blanks from the words A to F given below’.
A: Decreases
B: Increases
C: Remains same
D: Increases by one
E: Electropositive
F: Electronegative
Across a period from left to right in the Modern Periodic Table.
No. of electron shells _________; No. of valence electrons __________: Electronegativity increases Character of elements changes from electropositive to ________.
