Classification of elements into blocks — lesson. Science State Board, Class 9.

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Four blocks of elements:

We know that the electrons in an atom are arranged in shells around the nucleus.
Each shell comprises one or more subshells in which the electrons are shared in a particular manner. These subshells are named s, p, d, and f.
Based on the order of electrons in subshells, the periodic table elements are divided into four blocks: s, p, d and f.

s-Block Elements:

1. Alkali metals:

It contains groups \(1\) (alkali metals) and \(2\) (alkaline earth metals) elements.
They are also named as representative elements.
Except for hydrogen, the elements in group \(1\) are metals.
When they react with water, they form solutions that turn red litmus paper in to blue.
These solutions are classified as highly alkaline or basic. As a result, they are known as alkali metals.

2. Alkaline earth metals:

The group \(2\) elements are metals.
They react with oxygen to form oxides, formerly known as 'earth,' and these oxides contain alkaline solutions when dissolved in water.
As a result, these elements are known as alkaline earth metals.

p-Block Elements:

These elements are found in periodic table groups (\(13\)-\(18\)).
In addition to noble gases, they include the boron, carbon, nitrogen, oxygen, and fluorine families (except helium).
They are also named as representative elements.
The p-block is home to the widest variety of elements and is the only block that includes all three types of elements: metals, non-metals, and metalloids.

d-Block Elements:

It contains elements from groups (\(3\) to \(12\)).
They are located in the middle of the periodic table.
These block elements' properties are intermediate to that of s and p block elements. Hence, they are called transition elements.

f-Block Elements:

It contains \(14\) elements named Lanthanoides after (Lanthanum) La (\(57\)) and \(14\) elements called Actinoides after (Actinium) Ac (\(89\)).
They are fixed at the bottom of the periodic table.
They are also named as inner transition elements.

Reference:

https://upload.wikimedia.org/wikipedia/commons/b/b6/PTable_structure.png

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4. Classification of elements into blocks