info@urfaculty.com

www.urfaculty.com

Govt. Job/ Sarkari Naukri, NEET, CAT, Bank Exam & Study materials

Friday, 10 February 2017

The p-block elements II


• The atomic and ionic radii of group 13 elements are compared to corresponding elements of group From left to right in the period, the magnitude of nuclear charge increases but the electrons are added to, the same shell. These electrons do not screen each other, therefore, the electrons experience greater nuclear charge.

• In other words, effective nuclear charge increases and thus, size decreases. Therefore, the elements of this group have smaller size than the corresponding elements of second group.


• On moving down the group both atomic and ionic radii are expected to increase due to the addition of new shells. However, the observed atomic radius of Al (143 pm) is slightly more than that of Ga (l35 pm).


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 3rd 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.

Click here to view complete Chemistry Free Study Materials and Notes for NEET Preparation

Click here to view complete Physics Free Study Materials and Notes for NEET Preparation

Click here to view complete Biology Free Study Materials and Notes for NEET Preparation

Click here to take NEET online practice tests by UrFaculty.com

No comments:
Write comments

Hey, we've just updated our test package. Check'it out here - https://goo.gl/r7FuPT
Join Youth Apps