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Classification of Elements and Periodicity in Properties - Practice Questions & MCQ

Edited By admin | Updated on Sep 18, 2023 18:34 AM | #JEE Main

Quick Facts

Classification of Elements : s-block is considered one of the most asked concept.
38 Questions around this concept.

Element not showing variable oxidation state is :

Chlorine

Iodine

Bromine

Fluorine

Classification of Elements : s-block

The elements having ns¹ and ns² electronic configurations in their outermost shell are called s-block elements.
Elements with ns¹ configuration are called group 1 (alkali elements).
Elements with ns² configuration are called group 2 (alkaline earth elements).
They are highly reactive and readily form univalent or bivalent positive ions by losing the valence electrons.
The elements of this block are soft, malleable and good conductors of heat and electricity.
The elements have largest atomic and ionic radii but lowest ionization energies.
They show fix valency and oxidation states.
The loss of the outermost electrons(s) occurs readily to form M⁺ (in case of alkali metals) or M²⁺ ions (in case of alkaline earth elements).
Except beryllium compounds all other compounds of this block elements are predominantly ionic.
They are soft metals having low melting points and boiling points.
These metals and their salts impart characteristic colour to the flame. For example, sodium salt imparts a golden yellow colour to flame.
The elements of this group have large size, strong reducing nature, high electropositive nature, very low electronegativity values, ionization energy and electron affinity.

Classification of Elements : p-block

The elements whose last electron enters into any p-orbital are known as p-block elements.
The general outer electronic configuration for these elements is ns²np^1-6.
Group 13 or III A have one electron in p-orbital whereas group 18 or VIII A (inert gas) have 6 electrons in their outer p-orbitals. The outer p-orbitals in an inert gas are fully-filled with electrons.
They include both metals and nonmetals but there is a regular change from metallic to non-metallic character as we move from left to right across the period.
These elements do not impart colour to the flame test.
Except F and inert gases, all other elements of this block show variable oxidation states.
They have quite high ionization energies and the values tend to increase as we move from left to right across the period.
They form covalent compounds mostly like oxides, halides, sulphides, carbonates, etc.
Except metals, the other elements of this block are nonconductors.
A number of elements of this block show catenation property and allotropy like C, Si, Ge, S, O etc.
As we move from left to right, there is a gradation from reducing to oxidizing properties.

Classification of Elements : d-block

The d-block is in between s and p blocks. In these elements, their last electron enters into any of the d-orbitals. These elements are also known as transition elements as their properties are in between s and p-block elements.
The general electronic configuration of d-block elements is (n-1)d^1-10ns^1-2.
These elements are in between 2-13 group in the periodic table.
They show variable valency and oxidation state in their chemical bond formation.
These metals have high values of melting points, boiling points, densities, thermal stability and hardness.
They are ductile and malleable.
They are good conductors of heat and electricity due to the presence of free electron.
They form coloured ions and complexes.
Metals and their ions are generally paramagnetic in nature because of the presence of unpaired electrons.
These metals form a number of alloys as they have almost similar sizes.
These metals and their compounds are widely used as catalysts.
These metals also form nonstoichiometric and interstitial compounds with small size atoms like H, C, N, O which can be easily fitted in the vacant sides of the lattices of these metals. For example, Fe_0.93O.

Classification of Elements : f-block

The elements placed in two separate rows at the bottom of the periodic table are f-block elements.
These elements have their last electron enters into the f-orbital.
The elements from cerium to lutetium having incomplete 4f-orbitals are known as lanthanoids.
The elements from thorium to lawrencium having incomplete 5f-orbitals are known as actinides.
The general electronic configuration of f-block elements is (n-2)f^1-14(n-1)d^1-2ns².
Many of actinide elements have been made only in nanogram quantities or less by nuclear reactions and their chemistry is not fully studied.
Many of them are synthetic elements.
The elements coming after uranium are called transuranium elements.
They are metals having high melting and boiling points.
They show variable oxidation states however their most common and stable oxidation state is +3.
They form coloured ions and complexes.
Actinides are radioactive in nature.