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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
Explain why, the noble gases are placed in a separate group.
State whether the following statement is true or false:
On going down in a group of the periodic table, the number of valence electrons increases.
Explain why all the elements of a group have similar chemical properties.
On the basis of electronic configuration, how will you identify chemically similar elements?
State the term
The tabular arrangement of elements in horizontal rows and vertical columns _________
Two elements P and Q belong to the same period of the modern periodic table and are in group 1 and group 2, respectively. Compare the following characteristics in the tabular form.
- Number of electrons in their atoms
- Their tendency to lose electrons
- Their metallic characters
- Formation of their oxides
- Formulae of their chlorides
Give the chemical formula of sodium hydroxide
Distinguish between:
s-block - p-block
Choose an element from period 3 of modern periodic table that matches the description given below in instance. Give a reason for your choice.
It has variable valency and is a member of the Oxygen family (group 16).
An element has 2 electrons in its N shell.
State its position in periodic table.
