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प्रश्न
State the modern periodic law for the classification of elements. How many (i) groups and (ii) periods are there in the modern periodic table?
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उत्तर
Modern Periodic Law:
The physical and chemical properties of elements are a periodic function of their atomic numbers.
- There are 18 vertical columns called groups (numbered from 1 to 18).
- There are 7 horizontal rows called periods (numbered from 1 to 7).
संबंधित प्रश्न
How does the metallic character of elements in Modern Periodic Table vary on moving from left to right in a period, and (ii) down a group?Give reason to justify your answer.
How does the chemical reactivity of alkali metals vary on going in group 1 of the periodic table?
What is the usual number of valence electrons and valency of group 18 elements of the periodic table?
Name the scientist who stated the modern periodic law.
Name and state the following with reference to the elements of the first three periods of the periodic table.
A covalent compound formed by an element in period 2 and a halogen.
An element A has 2 electrons in its fourth shell. State its electronic configuration.
Give the symbol and valency of the following element and radical.
Hydrogen
State whether true or false. If false, correct the statement.
Lanthanides and actinides are kept at the bottom of the periodic table because they resemble each other but they do not resemble with any other group elements.
The element which has the least tendency to lose electrons is ______
A part of modern periodic table is given below. On its basis, answer the following questions:
| Group No. → | 1 | 2 | 13 | 14 | 15 | 16 | 17 | 18 |
| Period ↓ | ||||||||
| 2 | A | B | ||||||
| 3 | E | D | F | C |
Write the molecular formula of the compound formed by the combination:
A and F
