Question

explain S block element

briefly

Answer 1

heya @user
here is your answer

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s-block elements :-
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the elements in which the last electron enters the s-orbital of their outermost orbit are called as block elements.

⭕ General Configuration - ns¹ or ns²

⭕ since s-subshell can contain Maximum two electrons so there are only two groups in the s-block i.e. group 1 and 2

⭕ the elements crossponding to ns¹ outer configuration are called alkali earth metal (except H) while those corresponding to ns² configuration are called alkaline earth metals.

EXAMPLE -
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Alkali metals (ns¹) - H, Li, Na, K, Rb, Cs and Fr

Alkaline earth metal (ns²) - Be, Mg, Ca, Sr, Ba and Ra

CHARACTERISTICS OF s-block ELEMENTS :-
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⭕ They are soft metals having low melting point and boiling point.
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NOTE:-

alkaline earth metals are harder than alkali metals.

There is not any specific trend of m.p., b.p. and hardness of alkaline earth metal due to difference crystalline form.
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⭕ they are very relative and hence Don't exist in nature in free state.

⭕ the s-block elements show fixed valency.

⭕ the s-block elements show fixed Oxidation state in their compounds.

⭕ they are strong reducing agent

⭕ they form ionic compounds. { except H, Li, Be }

⭕ they form ionic/saline hydrides

⭕ they form basic oxides

⭕ they are good conductors of heat and electricity.

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Answer 2

Hey.....!!!! :)) ✌️✌️
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S Block element :- The elements in which the last electron enters the outermost s-orbital are called s-block elements. 

The s- is one of four s of elements on the periodic table. The s- group have a common property. The electron in their most outward electron shell are in thes-orbital. Elements in the s- are in the first two periodic table groups. Theelements in group one are called the alkali metals.

S - Block elements :-

Element's Atomic number
Hydrogen (H). 1

Lithium (Li). 3

Sodium ( Na) 11

Potassium (k) 19

Rubidium ( Rb) 37

Caesium ( Cs) 55

Francium ( Fr) 87

Physical properties of S - Block :-

<> Physical state: all the elements exist as silvery white, soft and light metals. These are considered as metals due to very low ionisation energies.

<> Atomic radius:as we know alkali metals are the largest elements of the corresponding periods. Atomic radius increases from lithium to Francium as we move down the period.

<> Oxidation State:as alkali metal atoms have only one electron in the valence shell, they exhibit an oxidation state of +1. By losing one electron, these alkali metals form a unipositive ion that has a noble gas configuration. Hence, it is very difficult to remove an electron from these metal ions resulting in very high second ionization energies.

<> Conductivity:: Due to the presence of a single electron that can be easily removed in the valence shell, alkali metals act as very good conductors of heat and electricity. Conductivity increases from Li to Cs.

<> Electro negativity:they show very less tendency to attract electrons i.e. very low electronegativity. Electronegativity decreases from Li to Cs.

<> Hydration Energy: it is the energy liberated at the time of hydration. As the degree of hydration decreases as we move down the period, hydration energy decreases from Li to Cs.

Chemical properties of S - Block elements :-

<> Reaction with water: 

Alkali metals react with water and form hydroxides along with liberation of hydrogen. This can be given as 

2M + 2H2O --- => 2MOH + H2

<> Reaction with hydrogen: 

Alkali metals react with hydrogen and form ionic hydrides of the form M+ H-. These metal hydrides in turn react with water to give back the hydrogen. These two reactions are as given below: 

2M + H2 --- => 2MH 

MH + H2O --- => MOH + H2

<> Action of Air: 

Alkali metals lose their lustre very easily upon exposure to air. To prevent the alkali metals from tarnishing, they have to be preserved under paraffin oil or kerosene.

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I hope it's help you......!!! :)) ✌️✌️