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प्रश्न
What is meant by ‘period number’. What does it signify?
उत्तर
Period number: “Period numbers 1, 2, 3, 4, 5, 6, 7 signifies – no of electron shells of an element.”
i.e. period no. 2 signifies the second shell from the nucleus
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संबंधित प्रश्न
The atomic number of an element is more important to the chemist than its relative atomic mass. Why?
Complete the table:
|
Atomic number |
Element |
Electronic configuration |
Select an element of the same group |
|
11 |
Sodium |
|
(Ca/N/K)… |
|
15 |
Phosphorus |
|
(Ba/N/Rb)… |
|
16 |
Sulphur |
|
(F/Cl/O)… |
|
9 |
Fluorine |
|
(Ca/Cl/K)… |
Relative atomic mass of a light element up to calcium is approximately ______ its atomic number.
An element A has 2 electrons in its fourth shell. State:
its atomic number
Give a reason for the following:
Properties of elements are periodic functions of their atomic numbers and not atomic weights.
In Modern Periodic Table the number of columns and periods are respectively _______ and _______.
Modern periodic law states that the physical and chemical properties of elements are the periodic functions of their ______.
State modern periodic law.
The basis of modern periodic law is ______.
| Group in the modern periodic table | Families |
| 1 | ______ |
| ______ | Transition metals |
| ______ | Boron family |
| 15 | ______ |
| 17 | ______ |
