s-block Elements

The "s-block" in the periodic table refers to the two groups of elements located in the leftmost part of the periodic table: Group 1 and Group 2. These elements are characterized by their outermost electrons occupying the s orbital of their respective electron shells.

1.0What are s-block Elements?

The s-block elements in the Periodic Table are those where the last electron enters the outermost s-orbital. Two groups, 1 and 2, belong to the s-block. Here is s-block element’s position in periodic table-

Group 1 includes- Lithium, Sodium, Potassium, Rubidium, Caesium, and Francium, collectively known as the alkali metals. They are named so because they form strongly alkaline hydroxides when reacting with water. 

Group 2 comprises- Beryllium, Magnesium, Calcium, Strontium, Barium, and Radium. Except for beryllium, they are known as the alkaline earth metals, as their oxides and hydroxides are alkaline and are commonly found in the earth’s crust.

Alkali metals and alkaline earth metals are both groups of elements found in the s-block of the periodic table, but they have distinct differences in their properties and reactivities.

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2.0Electronic Configuration of s-block Elements 

Group- 1 Electronic Configuration-

Group-2 Electronic Configuration-

3.0Properties of s block

Here we will discuss some unique and important properties of s-block elements. 

Physical Properties of s-block Elements

Note- In s-block elements Beryllium (Be) has the smallest size, while Caesium (Cs) has the largest size.

Note- In s-block elements Be has smallest size, while Cs has largest size.

Flame test- The flame test is a method used to identify the presence of certain metal ions in a compound by observing the color of the flame when the compound is heated. Different metals produce characteristic flame colors due to electronic transitions, allowing for qualitative analysis.

Chemical Properties of s-block Elements

1. Reactivity- 

2. Reactions with air-

4.0Important Compounds of s-block Elements

NaCl (Sodium Chloride):

• Properties: It is a white crystalline solid with a high melting point. It is highly soluble in water and forms a salty solution.
• Uses: Commonly known as table salt, it is used as a seasoning and preservative in food. It is also used in the production of chemicals, in the food processing industry, and in water softening.

NaOH (Sodium Hydroxide):

• Properties: It is a white solid at room temperature, highly soluble in water, and forms a strongly alkaline solution.
• Uses: Sodium hydroxide is widely used in the manufacture of pulp and paper, textiles, soaps, detergents, and various types of cleaners. It is also used in the production of biodiesel, as a pH regulator in water treatment, and in many chemical processes.

NaHCO₃ (Sodium Bicarbonate):

• Properties: It is a white crystalline solid with a slightly alkaline taste. It is moderately soluble in water.
• Uses: Sodium bicarbonate, commonly known as baking soda, is used as a leavening agent in baking. It is also used as an antacid to relieve heartburn and indigestion. Additionally, it finds applications in cleaning and deodorizing.

Na₂CO₃ (Sodium Carbonate):

• Properties: It is a white, odorless solid, soluble in water. It is alkaline in nature.
• Uses: Sodium carbonate, also known as soda ash or washing soda, is used in glassmaking, detergent production, and in the manufacturing of various chemicals. It is also used in water treatment processes and as a pH regulator in swimming pools.

CaO (Calcium Oxide):

• Properties: It is a white, caustic solid with a high melting point. It reacts vigorously with water to form calcium hydroxide.
• Uses: Calcium oxide, also known as quicklime, is used in various industrial processes such as steelmaking, water treatment, and the production of cement, paper, and chemicals. It is also used in agriculture to neutralize acidic soils.

Ca(OH)₂ (Calcium Hydroxide):

• Properties: It is a white powder with low solubility in water. It forms a strong alkaline solution.
• Uses: Calcium hydroxide, commonly known as slaked lime, is used in construction (mortar and plaster), wastewater treatment, and as a pH regulator in agriculture. It is also used in food processing (pickling) and as an ingredient in toothpaste and antacids.

CaSO₄ (Calcium Sulfate):

• Uses: Calcium sulfate is commonly found in two forms:
• Gypsum (CaSO₄·2H₂O): Used in the construction industry for making plaster of Paris, plasterboard, and cement.
• Anhydrous Calcium Sulfate (CaSO₄): Used in agriculture as a soil conditioner and in brewing as a water conditioner.

Plaster of Paris:

• Properties: It is a white powder that hardens when mixed with water.
• Uses: Plaster of Paris, made by heating gypsum to remove water molecules, is used in construction for making casts, molds, and sculptures. It is also used in medicine for casting broken limbs and in dentistry for making dental impressions. Additionally, it finds applications in art and crafts for creating sculptures and decorative items.