s,p,d and f Block Elements

The periodic table is a systematic tabular arrangement of all the chemical elements. It is a graphic representation of the law, which claims that the properties of chemical elements are related to their atomic numbers in a predictable manner. The periodic law states that “The physical and chemical properties of the elements are periodic functions of their atomic numbers”.

There are seven periods and eighteen groups within the periodic table. The rows in the periodic table are called periods, and the columns are called Groups. The periodic table has four general categories based on the subshells into which the valence electron is inserted.

The periodic table is classified into four blocks based on which subshell the valence electron enters. They are namely s,p,d and f blocks.

s Block Elements

The s block elements are situated at the extreme left side of the periodic table. They include Group 1 elements (Alkali metals), Group 2 elements(Alkaline earth metals), Hydrogen and Helium. They are called s block elements because the valence electrons enter the s subshell. Their general electronic configuration ns1-2.

Properties of s block elements

• They are highly reactive metals.

• They have low melting and boiling points.

• They are excellent conductors of electricity.

• They mainly form ionic compounds.

• They give characteristic colour to the flame.

• They are electropositive and form basic oxide.

p Block Elements.

The p block elements are situated at the extreme left side of the periodic table. They include elements in Group 13 (Boron family), Group 14 (Carbon family), Group 15 (Nitrogen family), Group 16 (Chalcogens), Group 17 (Halogens) and Group 18 (Noble gases).

The last electron enters the p orbital, hence the name p-block elements.

 The general electronic configuration is np1-6.

Properties of p block elements

• p blocks include metal, nonmetals and metalloids.

• The elements are shiny and good conductors of heat and electricity.

• The metallic character increases down the group.

• They mostly form covalent compounds. Oxygen and halogens tend to form ionic compounds with metals.

• They show variable oxidation states.

• The reactivity of the metals decreases down the group.

d Block Elements

The d block, also called transition metals, is found between the s block and p block elements. The last electron of these elements enters the penultimate d subshell and hence have the named block elements. They are called transition elements because they show a transition from highly reactive ionic metals in the s block to non-covalent metals in the p block.

The general electronic configuration of the d block element is (n-1)1-10ns1-2.

They include the elements from Group 3 to Group 13. 

There are four series within the d block concerning the filling of electrons. They are 3d, 4d, 5d and 6d series.

First transition series or 3d series – Scandium to Zinc

Second transition series or 4d series – Yttrium to Cadmium

Third transition series or 5d series – Lanthanum to Mercury(except Lanthanoids)

Fourth transition series of 6d series – Actinium to copernicium(except Actinoids)

Properties of d block elements

• d block elements are metals with high melting and boiling point

• They display all the metallic characteristics like malleability and ductility. They have good tensile strength.

• They have high thermal and electrical conductivity.

•  The compounds formed are paramagnetic.

• They include coloured compounds and exhibit variable oxidation states.

• They have great catalytic power and are used as catalysts in many reactions.

f Block Elements

The f block elements or the inner transition elements are found at the bottom of the periodic table separate from the other blocks. In f block elements, the last electron enters the anti penultimate f subshell. The general electronic configuration is (n-2)1-14(n-1)d0-1ns2.

The f block elements are classified into two based on which f subshell the last electron enters. They are 4f or Lanthanides and 5f or Actinides.

Lanthanides 

– Cerium (Z=57) to Lutetium (Z=71)

– general electronic configuration is 6s25d0-14f1-14

-Almost all the elements are not radioactive, except Promitium(Pm)

Properties of Lanthanides

• They are soft silvery-white metals

• They are primarily non-radioactive except Promethium(Pm)

• The melting point ranges from 1000 K to 1200K

• From Lanthanum to Lutetium, there is a decrease in atomic and ionic size. This phenomenon is called Lanthanoid contraction.

Actinides

 – Thorium (Z=90) to Lawrencium (Z= 103)

– General electronic configuration is 7s26d0-15f1-14

Properties of Actinides

• The elements after Uranium are radioactive and are called transuranium elements

• They are silvery

• Actinides are highly reactive, and reactivity increases when they are finely powdered

• There is a decrease in atomic radii from Actinium to Lawrencium, known as Actinoid contraction.

Conclusion

The periodic table is a systematic tabular arrangement of all the elements. It is divided into four blocks: s, p, d and f. This division is dependent on which shell the valence electron enters. In the s block, the electron enters the s subshell. They are highly reactive metals, including alkali metals, alkaline earth metals, hydrogen and helium.

 In p block elements, the last electron enters the p subshell. They include groups 13 to 18 and include metals, nonmetals, and metalloids. In the d block, also known as transition metals, the valence electron enters the penultimate d subshell. They are metals with variable oxidation states and high catalytic power. The f block elements or inner transition elements, the entering of valence electrons takes place in the penultimate f subshell. They are divided into Lanthanides and Actinides.