Ionization energies
The first ionization energies of group 13 elements are less than the corresponding members of the alkaline earths .
The sharp decrease in I . E . from B to Al is due to increase in size . In case of Ga , there are ten d-electrons in its inner electronic configuration .
The very high value of 3 rd I . E . of thallium indicates that + 3 O . N . state is not stable , rather + 1 is more stable for thallium .
Electropositive ( or metallic ) character
the elements of group 13 are less electropositive as compared to elements of group 2 . On moving down the group the electropositive ( metallic ) character increases because ionization energy decreases . For e . g ., Boron is a non-metal white the other elements are typical metals .
Oxidation states
The common oxidation states of group 13 elements are + 3 and + l . The stability of the + 1 oxidation state increases in the sequence Al < Ga < In < Tl , Due to Inert pair effect .
Element |
B |
Al |
Ga |
In |
Tl |
Oxidation state |
+ 3 |
+ 3 |
+ 3 , + 1 |
+ 3 , + 1 |
+ 3 , + 1 |
Chemical reactivity of Gr . 13 Elements All elements in their compounds exhibit the oxidation state of + 3 and + 1 . Hydrides
• None of the group 13 elements reacts directly with hydrogen . However , a no . of hydrides of these elements have been prepared by indirect methods . The boron hydrides are called boranes & classified in two series :
( a ) |
BnHn + 4 called nidoboranes |
( b ) |
BnHn + 6 called arachnoboranes |