The alkali metals and alkaline earth metals, often known as groups 1 and 2, are located in the s-block of the periodic table of elements. Helium is also classified as an element of the s block. The s orbital is filled by the fundamental quantum number “n.” The s orbital can hold a maximum of two electrons.

The final electron in the s-block elements reaches the ns energy shell. Because the ns energy shell has a maximum capacity of two electrons, these elements have a valence shell configuration of either ns1 or ns2.

The elements that comprise this block are located on the far left of the Periodic Table. Alkali metals (Group IA elements) are those with a ns1 configuration, while alkaline earth metals have a ns2 configuration (Group IIA elements). s-block elements are frequently referred to as reactive metals.

Characteristics of s-block Elements in General-

The following are the general properties of alkali metals (Li, Na, K, Rb, Cs, and FrY) and alkaline earth metals (Be, Mg, Ca, Sr, Ba, and Ra), i.e. s-block elements:

• They are soft metals with low melting and boiling temperatures, the biggest atomic radii in their respective periods, and excellent thermal and electrical conductors.
• Due to their low ionisation energies, they are extremely electropositive.
• They have a high degree of reactivity and rapidly form ionic compounds. They have a fixed valency that is proportional to the number of electrons in the outermost shell. Monovalency is observed in alkali metals, whereas divalency is observed in alkaline earth metals. Due to their reactive nature, they are never encountered in a free condition in nature.
• They act as strong reducing agents due to their low ionisation energies and extremely negative electrode potentials. The alkali and alkaline earth metals cannot be synthesised via electrolysis of their salt solutions in water.
• With the exception of Be and Mg, they provide a distinct colour to the flame.
• s-block element compounds are primarily ionic and colourless. Lithium and beryllium compounds, on the other hand, are covalent in nature.
• They exhibit a strong affinity for oxygen and nonmetallic elements. Oxides are alkaline. Hydroxides are extremely alkaline
• They act as hydrogen scavengers in acids, forming equivalent salts.
• Except for Be and Mg, they rapidly break down water and generate hydrogen.

Physical and Chemical Properties-

The contemporary periodic table is the culmination of multiple versions of tables produced over millennia by scientists. This format is based on Mendeleev’s 1869 periodic table. Since that time, the world of chemistry has changed dramatically. We gained a better knowledge of the elements’ behaviour. This section will examine the s block elements that are classified as Group IA and IIA elements on the contemporary periodic table.

 The metals in the first group are referred to as alkali metals. Alkaline earth metals are included in the second group. The term’s block’ refers to elements whose electronic configuration of the valence shell is constrained to the S-suborbital. Due to the suborbital’s maximum capacity of two, we will only have two groups. S-block elements are all elements with the valence shell configurations ns1 or ns2.

Elements’ Properties

• There are a total of 14 s block elements (Group IA and IIA).
• These are soft elements with low boiling and melting points.
• Because the atomic radii of the periodic table’s block elements are larger, they have a low ionisation potential and behave as strongly electropositive elements.
• These elements in the s block of the periodic table are extremely reactive and rapidly combine to produce compounds with a fixed valency (1 or 2).
• Due to their high negative electrode potential, these metals are strong reducing agents.
• All elements, with the exception of magnesium and beryllium, have a distinct flame colour and rapidly react with water to generate alkalis and release hydrogen.

Alkali Metals -Alkali metals are elements classified in Group IA due to their ns1 valence shell electronic structure. These s block elements have the largest atomic radii in the era due to their low electron count. The following is a list of alkali metals’ physical and chemical properties. As with the s block elements, alkali metals are soft and solids of silvery-white colour. Due to the existence of one electron in the outermost valence shell, the crystals have a low lattice energy, which results in low melting and boiling points.

Due to the loosely bonded electrons in the outermost shells, these s block elements are referred to as good conductors of electricity and heat. They are able to move freely due to their low ionisation energy levels.

Alkaline Earth Metals-These elements are extremely reactive and are always found in combination. Indeed, they have a higher density than alkali metals. These s block element names are referred to as alkaline earth metals due to their presence as oxides in the earth

The melting and boiling temperatures of this alkali metal are higher than those of the previous alkali metals that existed during the same time period

From Beryllium to Barium, the first and second ionisation energies decrease. Indeed, the first ionisation energy is half that of the second.

Periodic Trends in the Elements of the S-Block

The periodic patterns in the contemporary periodic table can be used to anticipate the attributes of the s-blocks elements. These periodic trends are patterns in the elements’ characteristics. The following sections address the explanations for these periodic trends

• Atomic Radius – Alkali metals have a larger atomic radius than other metals in the s-block. The amount of electrons grows as the atomic number increases. As a result, the atomic radius of elements decreases as they progress through the group. This radius shrinks over time.
• Electro positivity – This property increases as the group progresses and decreases as the period progresses.
• Metallic Characteristics – The metallic properties of the s-block elements grow from top to bottom and diminish from left to right.
• Nonmetallic Character – The nonmetallic nature of the elements reduces as they progress through the group and increases as they progress through time.

CONCLUSION- 

In general, they are bright, silvery, strong conductors of heat and electricity and lose their valence electrons easily. In fact, they lose their signature s orbital valence electrons so easily that the s-block elements are considered to be among of the most reactive elements on the periodic table