Periodic Blocks (Modern )

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Modem Periodic law

Modem periodic law was given by Moseley. According to Moseiev : "The physical and chemical properties of the elements are the periodic function of their atomic numbers.

In modern periodic table :
  Period — 7
  Group — 18

Modern periodic table are classified as
  (i) s-block
  (ii) p-block
  (iii) d-block
  (iv) f-block

1. S-Block

It contains groups 1 and 2. The general electronic configuration of these elements is ns0-2 .

2. P-Block

It comprises the last six groups, and general electronic configuration of this block elements is ns2np1-6. It is the only block that contains metals, non-metals, and metalloids. Heavier elements show inert pair effects. S- and P-block elements are collectively called representative elements.

3. d-Block

It comprises 10 groups (3 to 12 ). These elements are called transition elements, general electronic configuration of d block is (n-1) d1-10ns1-2. Elements of this block contain unpaired electrons and are paramagnetic. These elements are generally transition metals but some elements are not in transition category.
Example : Zn, Cu, and Se.

4. f-BIock

General electronic configuration of d-block elements is (n -2) f1-14(n-1)d1-10ns1-2. There are two series in this block, 4f and 5f series. 4f series elements are called lanthanides, and 5f series elements of this block are called inner transition elements and present in IIIB group only.

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