You wouldn't know it before it hits you square in your head
I mean, I don't blame you, who would have thought an innocent group residing in the peaceful p block , could curse us all with all its notorious exception!
Before you know it, you are running out of the room, pulling the hair out of your head.
Yeah, In this blog we are going to be dealing with 5 elements in the periodic table, which are part of the 13th group.
Boron
Aluminium
Gallium
Indium
Thallium
Atomic Radii
Most of the periodic table follows this :- Orbits are added as we move down the period, so obviously the size increases.
Boron family doesn't
Boron < Gallium < Aluminium < Indium < Thallium
Why? Because of poor screening effect provided by the d-electrons , Gallium is smaller than Aluminium
( Note:- Ionic Radii follows the expected trend, increasing down the group)
Ionization Enthalpy
Ionization Enthalpy, the energy required to remove an electron from the outermost shell, is supposed to decrease down the group
But,
Boron> Thallium > Gallium > Aluminium > Indium
Boron family decides to follow this bonkers order.
This again follows a similar reason, due to poor screening effect of d-electrons and f-electrons in Gallium and Thallium respectively , it ends up jumping up the list.
Electronegativity
This is the only family where Electronegativity increases after Aluminium
Boron > Thallium > Indium > Gallium > Aluminium
Melting Point
Boron > Aluminium > Thallium > Indium > Gallium
Born forms a crystalline solid hence has a high melting point. Gallium in the other hand, is known as summer-liquid, turning into liquid state at a temperature little higher than room temp.
(Boiling point follows the regular trend of the periodic table)
Lewis Acid
For example, when Boron bonds to form BCl3, it doesn't get a complete octet configuration. Due to lack of electrons, this entire family acts like a Lewis Acid.
BX3 > AlX3 > GaX3 > InX3 > TlX3
shows the order of strength of the Lewis Acid
BF3 < BCl3 < BBr3 < BI3
(Bonds of elements like AlCl3 and GaCl3 is covalent while Anhydrous, but once in water becomes Ionic)
-- That marks the end of this blog. A very short blog, ik, that is as much I can tolerate with inorganic chemistry in one shot 😂, jkjk
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