This document discusses the properties of transition elements, specifically the first transition series elements from Scandium to Zinc. It provides information on their electronic configuration, atomic and ionic radii, ionization potential, and oxidation states. The key points are: 1) The first transition series elements belong to the 3d series, with their last electron entering the 3d subshell. Their general electronic configuration is [Ar] 4s1-2, 3d1-10. 2) Their atomic and ionic radii depend on nuclear charge, number of shells, and screening effect. 3) Ionization potential also depends on these three factors and represents the minimum energy required to remove an electron.

1. Vidyabharti College Seloo
Department of Chemistry
Class :- B.Sc. Third Sem.
Presented by :-

2. Introduction :-
According to modern classification, the elements have
been classified into s, p, d and f-block elements. The base
of this classifications is the position of last electron.
The elements in which last electron enters into s-subshell
are known as s-block elements, those in which last
electron enters into p-subshell are known as p-block
elements, those in which last electron enters into d-
subshell of last but one (n-1)th main shell are known as
d-block elements whereas, those in which last electron
enters into f-subshell of last but two (n-2)th main shell
are known as f-block elements.

3. The d-block elements are placed in between s and p –
block elements in the periodic table and have properties
intermediate between s & p – block elements. Hence
they are also known as transition elements.
3d- series is also known as first transition series
It includes ten elements from Scandium (21) to Zinc (30)

4. POSITION OF TRANSITION
ELEMENTS IN PERIODIC TABLE
The transition elements occupy or hold a central position
in the periodic table.
They are placed in between s-block elements and p-block
elements.
Whereas, in case of d-block elements, there is gradual
decrease in ionic character and increase in covalent
character from left to right in the periodic table, thus d-
block elements are known as transition elements.

5. S - block p- block
Fourth transition series
Second transition series
Third transition series
First transition series
Lanthanides
Actinides
Transition elements
Position of Transition elements in periodic table

6. GENERAL PROPERTIES OF
TRANSITION ELEMENTS:-
The d-block elements are peculiar in their properties. All
the d-block elements are metals. Due to the some of
their characteristic properties, d-block elements are
important, which are as under.
1. The d-block elements are metals having high melting
and boiling points.
2. Most of the transition elements are good conductors
of heat and electricity.
3. They have high densities due to smaller atomic sizes
& high atomic weights.

7. 4. They show variable oxidation states.
5. Their compounds are generally paramagnetic in nature.
6. They have a good tendency to form coloured
compounds and complexes.
7. Most of the transition elements such as Mn, Ni, Co, Cr,
V, Pt and their compounds are used as catalysts.
8. They are good reducing agents.

8. PROPERTIES OF
FIRST TRANSITION SERIES ELEMENTS
ELECTRONIC CONFIGURATION :-
First transition series elements i.e. Scandium (Sc=21) to Zinc
(Zc=30), belong to 3d series and thus, the last electron enters into
3d subshell.
First transition series includes elements from Scandium (21) to
Zinc (30). In case of Argon (Ar=18), the 18 electrons are distributed
as 1s2, 2s2, 2p6, 3s2, 3p6.
In Scandium (Sc=21), the next electron goes to 3d subshell
according to aufbau principle. Hence , Scandium is the first
element of transition series. After Scandium, each successive
electron adds to 3d subshell till its capacity is fulfilled. Hence, the
general electronic configuration is written as, [Ar] 4s1or2, 3d1-10.

10. ATOMIC AND IONIC RADII
Atomic radius :-
The distance of outer most electron from the center of nucleus in
an atom is known as atomic radius.
Ionic radius :-
The effective distance from the nucleus of the ion upto the point
of influence of nucleus is known as ionic radius.
The atomic or ionic radius are depends upon three factors, which
are as follows.
I. Nuclear charge
II. Number of shells
III.Screening effect (shielding effect)

11. IONIZATION POTENTIAL
“The minimum energy required to remove most loosely bound
outermost electron from isolated gaseous atom in its ground
state is known as ionization potential or ionization energy”.
The energy required to remove first electron from isolated
gaseous atom is known as first I. P., and energy required to
remove second electron is known as second I. P.
Ionization potential depends upon :-
I. Nuclear charge
II. Number of shells
III.Screening effect (shielding effect)

12. OXIDATION STATES:-
The number of electrons lost or gained by an atom during
formation of compound is known as its oxidation state. When
electron are lost, the oxidation states is positive. If electrons are
gained, oxidation state is negative.
All the metals have a tendency to show positive oxidation states by
loss of electron due to low values of their ionization potentials.
Minimum oxidation state :-
Except chromium and copper, all the elements show +2 as
minimum oxidation state. This is because of loss of two 4s
electrons whereas, in case of Cr and Cu, there is only one electron
in the 4s subshell. Hence, they show +1 as minimum oxidation
state.

13. Maximum oxidation state
Maximum oxidation state goes on increasing when we move from
left to right across the period i.e. from Sc to Mn. It is due to loss of
total number of electrons in 4s and 3d subshell. The maximum
oxidation state shown by 3d series element is +7 for Mn. Thus,
upto Mn, the maximum oxidation state is equal to number of
electrons in 3d and 4s orbitals.