p-block elements
Notes 1
The elements of group 13 to 18 are known as p-Block elements as in these
elements the last electron enters in p sub shell or p orbital. They lie on the right side
of periodic table. Along with s block they are called as representative elements.
2 1-6
General electronic configuration- [Rare gas] ns np
Max Oxidation state is equal to the total number of valance electrons i.e., (s+p
electron). It increases along the period. It is called as group oxidation state. They
also show diff oxidation state which differs from the total number of valence
electrons by 2 units. The occurrence of oxidation state two units less than group
oxidation states is due to inert pair effect.
Group 13 elements:
CALLED AS BORON FAMILY. Elements- Boron(B), Aluminium(Al), Gallium(Ga),
Indium(In) and Thallium(Tl). B- nonmetal and rest are metals.
Occurance-
• B- As orthoboric acid, borax and kernite.
• In India as borax- Puga valley and Sambhar lake. Two isotopic forms 10B and
11
B.
• Al- 3rd most abundant metal. As bauxite, cryolite and in India as mica in M.P,
Karnataka and Orissa. Rest elements are less abundant.
General properties:
ELECTRONIC CONFIGURATION-
B and Al have noble gas core and Ga and In have noble gas plus 10 d electrons and
Tl have noble gas plus 10 d and 14 f electronic core. Thus electronic configurations
are more complex.
Element Symbol Atomic Electronic
No. Configuration
Boron B 5 [He]2s2 2p1
Aluminium Al 13 [Ne]3s2 3p1
Gallium Ga 31 [Ar]3d104s2 4p1
Indium In 49 [Kr] 4d105s2 5p1
Thallium Tl 81 [Xe] 4f 145d106s26p1
ATOMIC RADII-
Down the group, one extra shell is added and hence radius increases. But Ga have
lesser radii than Al- this is due to the poor shielding effect by d electrons and more
E.N.C .
Notes 1
The elements of group 13 to 18 are known as p-Block elements as in these
elements the last electron enters in p sub shell or p orbital. They lie on the right side
of periodic table. Along with s block they are called as representative elements.
2 1-6
General electronic configuration- [Rare gas] ns np
Max Oxidation state is equal to the total number of valance electrons i.e., (s+p
electron). It increases along the period. It is called as group oxidation state. They
also show diff oxidation state which differs from the total number of valence
electrons by 2 units. The occurrence of oxidation state two units less than group
oxidation states is due to inert pair effect.
Group 13 elements:
CALLED AS BORON FAMILY. Elements- Boron(B), Aluminium(Al), Gallium(Ga),
Indium(In) and Thallium(Tl). B- nonmetal and rest are metals.
Occurance-
• B- As orthoboric acid, borax and kernite.
• In India as borax- Puga valley and Sambhar lake. Two isotopic forms 10B and
11
B.
• Al- 3rd most abundant metal. As bauxite, cryolite and in India as mica in M.P,
Karnataka and Orissa. Rest elements are less abundant.
General properties:
ELECTRONIC CONFIGURATION-
B and Al have noble gas core and Ga and In have noble gas plus 10 d electrons and
Tl have noble gas plus 10 d and 14 f electronic core. Thus electronic configurations
are more complex.
Element Symbol Atomic Electronic
No. Configuration
Boron B 5 [He]2s2 2p1
Aluminium Al 13 [Ne]3s2 3p1
Gallium Ga 31 [Ar]3d104s2 4p1
Indium In 49 [Kr] 4d105s2 5p1
Thallium Tl 81 [Xe] 4f 145d106s26p1
ATOMIC RADII-
Down the group, one extra shell is added and hence radius increases. But Ga have
lesser radii than Al- this is due to the poor shielding effect by d electrons and more
E.N.C .
