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Elements are grouped by different block names of s, p, d, f, based on categorising atoms in a periodic table. The s-block is situated on the left side of the periodic table and comprises elements from the first two columns, the nonmetals hydrogen and helium, and the alkali metals (in group 1) and alkaline earth metals (group 2). Let us understand the concept of S Block elements.
The s-Block of the periodic table comprises alkali metals of Group1 and alkaline earth metals of Group 2. Since the properties of S Block elements are alkaline due to the oxides and hydroxides, so is their nomenclature. These alkali metals have one s-electron, and the alkaline earth metals have two s-electrons in the valence shell of their atoms.
The 14 elements of S-Block The elements of S Block are hydrogen (H), lithium (Li), helium (He), sodium (Na), beryllium (Be), potassium (K), magnesium (Mg), rubidium (Rb), calcium (Ca), caesium (Cs), strontium (Sr), francium (Fr), barium (Ba), and radium (Ra).
Alkali metals are those which have only one electron in their s-orbital. They are also called group one metals. Alkaline earth metals are those which have two electrons filling their s-orbital. They are also called group two metals.
The alkali metals are silvery-white in colour. They are soft and have a low melting point. They are highly reactive, ionic, and soluble in water producing strong alkalies. Some of the important sodium compounds are sodium carbonate, sodium chloride, sodium hydroxide, and sodium hydrogen carbonate.
The chemistry of alkaline earth metals and alkali metals is similar.
However, their oxides, and hydroxides, are less basic than the alkali metal oxides and hydroxides. Calcium oxide (lime), calcium hydroxide (slaked lime), calcium sulphate (Plaster of Paris), calcium carbonate (limestone), and cement are industrially important compounds of calcium. An important construction material is Portland cement, which is manufactured by heating a pulverised mixture of limestone and clay in a rotary kiln.
Lithium (Li)- 1s22s1
Cesium (Cs)- [Xe]6s1
Magnesium (Mg) [Ne]3s2
Calcium (Ca) [Ar]4s2
Strontium (Sr) [Kr]5s2
Barium (Ba) [Xe]6s2
These elements of Group 1, as well as Group 2, display a regular phenomenon in their properties amid their individual group elements. It must be noted that Lithium and Beryllium deviate much from the other members, yet they also match more with the diagonal element existing in the subsequent column.
This exception of the S block elements is for the following reason;
It is perceived that the physical and chemical properties of S block elements change in a distinct trend with the increasing atomic number of the elements. Changes in the various properties of group 1 and group 2 elements are as stated below:
1. What are S block elements?
The elements that comprise Group 1 and Group 2 of the modern periodic table are called S block elements. The two types of s block elements are possible, they include the elements with one electron (s1) or the elements with two electrons (s2) in their s-subshell.
2. Why are S Block elements called S Block?
The s-block elements are referred to as the name suggests for their valence electrons are in an s orbital. They are also called Typical Elements to differentiate them from the transition and inner transition series.
3 How many elements are in an S Block?
There are 14 elements in the S block. As referred to above, they are; hydrogen (H), lithium (Li), helium (He), sodium (Na), beryllium (Be), potassium (K), magnesium (Mg), rubidium (Rb), calcium (Ca), caesium (Cs), strontium (Sr), francium (Fr), barium (Ba), and radium (Ra).
4. What are S Block elements Class 11?
The elements included in this class are beryllium, magnesium, calcium, strontium, barium, and radium.
5. Why ions of S block elements Colourless?
Alkali metals hold low ionisation enthalpies. Again in alkali metals, d-d transitions are not possible, which are probable in transition metal ions. So, the compounds which are formed by alkali metals are colourless and are also diamagnetic.
So 14 elements in S-Block of the periodic table consisting of alkali metals and alkaline earth metals show different physical and chemical properties. These properties have a definite trend, which differs while moving down the group as well as diagonally.
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