P block - 13th group Flashcards
What are p block elements?
Elements which fill their last electrons to a p-subshell
Common electron configuration of group 13
ns2 np1
Valency of group 13
3
Oxidation no. of group 13
+3
How does the metallic character vary down the group 13?
Metallic character increases down the group
Describe the metallic properties of B
it is a metalloid
Describe the metallic properties of Al
It’s a metal w/ amphoteric properties
Describe metallic properties of Ga, In, Tl
They’re metals
Why does B have special properties
Due to its small size
Describe the nature of most compounds of group 13
Covalent
What’s the most abundant metal in the earth’s crust?
Al
What’s the 3rd most abundant element in the earth’s crust?
Al
Why is Al considered non-reactive with air?
Al is reactive, but when exposed to air, an oxide layer of Al2O3 is formed.
This layer masks the inner metal and it becomes resistant to further reactions with O2
Write Al reactions with oxygen
Al + O2 —> Al2O3
Write Al reactions with halogens
2Al + 3Cl2 –> 2AlCl3
Write Al reactions with Nitrogen
Al + N2 —> AlN
Why is Al similar to Be?
Both are amphoteric
Write reactions of Al with acids
It gives salts and H2 gas with acids
Al + HCl –> AlCl3 + H2
Write reactions of Al with bases
Al + OH- + H2O –> 2[Al(OH2)4]- + H2
Al + OH- + H2O –> 2 AlO2- + 3H2
Describe the nature of the Al3+ aqueous solution
Al3+ ion in aqueous solution is expected to be [Al(OH2)6] or hexaaquaaluminum ion
But, hydrolysis of Al3+ produces pentaaquahydroxialuminum [Al(OH2)5(OH)]2+ and then tetraaquahydroxidoaluminum ion [Al(OH2)4(OH)2]+
[Al(OH2)6]3+ + H20 –>[Al(OH2)5(OH)]2+ + H3O+
[Al(OH2)5(OH)]2+ + H2O –> [Al(OH2)4(OH)2]+ + H3O+
Describe reactions of adding OH- ions to aluminum ions
First, a gelatinous precipitate of aluminum hydroxide is produced
With excess OH- ions, it is converted to tetrahydroxidoaluminate complex ion
Al3+ + OH- —> Al(OH)3
Al(OH)3 + OH- —> Al(OH)4- / AlO2- + 2H20
What are some electron deficient compounds produced by 13th group elements?
AlCl3
BCl3
Why are 13th group electron deficient compounds called lewis acids?
They can accept loan pairs
What are the dimers formed by B and Cl and why do they do it?
Al2Cl6
Both Al and B compounds form dimers in the gaseous phase to satisfy the octet rule
How does aluminum hydroxide appear as?
A white, gelatinous precipitate
