MDCAT
Chemistry
Quick Practice Book
www.nearpeer.org
Oldest, Largest and Most Credible Platform
, S and p - Block Elements
Learning Objectives:
Understand the trends in Physical Properties of elements belonging
period no 2 and period no 3.
Explain the periodicity in physical properties of elements
Atomic Radi
Ionic Radii
Ionization Energy
Electron Affinity
Melting Point
Boiling Point
Electrical Conductivity
Electronegativity
Reaction of Group IA elements with H2O, O2 and Cl2
Reactions of Group IIA elements with H2O, O2 and N2
Reactions of Group IIIIA elements with H2O, O2 and Cl2
s-block and p-block Elements (Inorganic chemistry)
,Introduction
The Periodic Table provides a basic framework to study the periodic behaviour of physical and
chemical properties of elements as well as their compounds.
Key Features of the modern periodic table which help you to understand the trends in
physical and chemical properties of elements.
Elements have been arranged on the basis of increasing atomic number. (The idea to
arrange elements on the basis of proton was first floated by Moseley).
There are 7 horizontal rows called periods (no of shells≈ periods) and 18 vertical
columns called groups.(valence electrons in representative elements ≈ groups).
Atomic properties gradually change as we move from left to right within same period
but shell no remains same.
The atomic properties; i.e., ionization energy, electron affinity, density,
electronegativity increases along the period from left to right with few exceptions.
Every period except first starts with metal and ends with non-metal.
The prominent periods; 3d transition series, 4d transition series, 5d transition series,
lanthanides and actinides show tremendous variations of properties.
Within same group, no of valence electrons remain same but no of shells changes as we
move from top to bottom. It accounts that similar elements are placed in same group.
The position of elements in groups greatly helps in understanding the pattern of
chemical reactivity.
The famous groups include alkali metals (IA), alkaline earth metals (IIA)noble
gases(VIIIA), Chalcogen (VIA)etc.
Depending upon the valence electronic configuration, modern periodic table has 4-
block division; s-block, p-block, d-block and f-block.
Another division of groupscomprises the division of groups into representative
elements (A) and transition elements (B).
Dobereiner Newlands Mendeleev Moseley Al Razi
Law of triad Law of Octave Periodic table Atomic number Four group div,
, Division of Modern Periodic Table into Block
s-block elements:
I-A and II-A group elements and Helium are called s-block because their valence electrons are
present in s-orbital.
p-block elements:
III-A to VIII-A group elements (except He) are called p-block elements because their valence
electrons are present in p-orbital.
d-block elements:
I-B to VIII-B group elements (transition elements) are called d-block elements because their
valence electrons are present in d-orbital.
f-block elements:
Lanthanides and actinides are called f-block elements because their valence electrons are
present in f-orbital.
Periodic trends in physical properties
Atomic radius:
“Half of the distance between the nuclei of two adjacent atoms is considered to be the radius
of the atom.”
Atoms are assumed to be spherical. Depending upon the type of the compound used
for its measurement, the sizes of atoms are expressed in terms of atomic radii, ionic
radii and covalent radii, etc.
The atomic radius increases from top to bottom within a group due to increase in
atomic number.
This is due to the addition of an extra shell of electrons.
Point to Ponder
Factors Affecting Atomic
Radius:
Nuclear Charge:
Figure 2: Atomic radius trend in alkali metals
As it increases, atomic radius
decreases.
No of Shells:
As it increases, atomic radius
increases.
Chemistry
Quick Practice Book
www.nearpeer.org
Oldest, Largest and Most Credible Platform
, S and p - Block Elements
Learning Objectives:
Understand the trends in Physical Properties of elements belonging
period no 2 and period no 3.
Explain the periodicity in physical properties of elements
Atomic Radi
Ionic Radii
Ionization Energy
Electron Affinity
Melting Point
Boiling Point
Electrical Conductivity
Electronegativity
Reaction of Group IA elements with H2O, O2 and Cl2
Reactions of Group IIA elements with H2O, O2 and N2
Reactions of Group IIIIA elements with H2O, O2 and Cl2
s-block and p-block Elements (Inorganic chemistry)
,Introduction
The Periodic Table provides a basic framework to study the periodic behaviour of physical and
chemical properties of elements as well as their compounds.
Key Features of the modern periodic table which help you to understand the trends in
physical and chemical properties of elements.
Elements have been arranged on the basis of increasing atomic number. (The idea to
arrange elements on the basis of proton was first floated by Moseley).
There are 7 horizontal rows called periods (no of shells≈ periods) and 18 vertical
columns called groups.(valence electrons in representative elements ≈ groups).
Atomic properties gradually change as we move from left to right within same period
but shell no remains same.
The atomic properties; i.e., ionization energy, electron affinity, density,
electronegativity increases along the period from left to right with few exceptions.
Every period except first starts with metal and ends with non-metal.
The prominent periods; 3d transition series, 4d transition series, 5d transition series,
lanthanides and actinides show tremendous variations of properties.
Within same group, no of valence electrons remain same but no of shells changes as we
move from top to bottom. It accounts that similar elements are placed in same group.
The position of elements in groups greatly helps in understanding the pattern of
chemical reactivity.
The famous groups include alkali metals (IA), alkaline earth metals (IIA)noble
gases(VIIIA), Chalcogen (VIA)etc.
Depending upon the valence electronic configuration, modern periodic table has 4-
block division; s-block, p-block, d-block and f-block.
Another division of groupscomprises the division of groups into representative
elements (A) and transition elements (B).
Dobereiner Newlands Mendeleev Moseley Al Razi
Law of triad Law of Octave Periodic table Atomic number Four group div,
, Division of Modern Periodic Table into Block
s-block elements:
I-A and II-A group elements and Helium are called s-block because their valence electrons are
present in s-orbital.
p-block elements:
III-A to VIII-A group elements (except He) are called p-block elements because their valence
electrons are present in p-orbital.
d-block elements:
I-B to VIII-B group elements (transition elements) are called d-block elements because their
valence electrons are present in d-orbital.
f-block elements:
Lanthanides and actinides are called f-block elements because their valence electrons are
present in f-orbital.
Periodic trends in physical properties
Atomic radius:
“Half of the distance between the nuclei of two adjacent atoms is considered to be the radius
of the atom.”
Atoms are assumed to be spherical. Depending upon the type of the compound used
for its measurement, the sizes of atoms are expressed in terms of atomic radii, ionic
radii and covalent radii, etc.
The atomic radius increases from top to bottom within a group due to increase in
atomic number.
This is due to the addition of an extra shell of electrons.
Point to Ponder
Factors Affecting Atomic
Radius:
Nuclear Charge:
Figure 2: Atomic radius trend in alkali metals
As it increases, atomic radius
decreases.
No of Shells:
As it increases, atomic radius
increases.
