NEET  >  Transition elements - NEET

Transition elements - NEET Notes - NEET

Document Description: Transition elements - NEET for NEET 2022 is part of NEET preparation. The notes and questions for Transition elements - NEET have been prepared according to the NEET exam syllabus. Information about Transition elements - NEET covers topics like and Transition elements - NEET Example, for NEET 2022 Exam. Find important definitions, questions, notes, meanings, examples, exercises and tests below for Transition elements - NEET.

Introduction of Transition elements - NEET in English is available as part of our NEET preparation & Transition elements - NEET in Hindi for NEET courses. Download more important topics, notes, lectures and mock test series for NEET Exam by signing up for free. NEET: Transition elements - NEET Notes - NEET

How we find colour of co ordination compounds as above que?
Ref: https://edurev.in/question/743286/How-we-find-colour-of-co-ordination-compounds-as-a

1 Crore+ students have signed up on EduRev. Have you?

Transition elements are usually characterised by having d orbitals. Now when the metal is not bonded to anything else, these d orbitals are degenerate, meaning that they all have the same energy level.

However when the metal starts bonding with other ligands, this changes. Due to the different symmetries of the d orbitals and the inductive effects of the ligands on the electrons, the d orbitals split apart and become non-degenerate (have different energy levels).

This forms the basis of Crystal Field Theory. How these d orbitals split depend on the geometry of the compound that is formed. For example if an octahedral metal complex is formed, the energy of the d orbitals will look like this:

Transition elements - NEET Notes - NEET

As you can see, previously the d orbitals were of the same energy, but now 2 of the orbitals are higher in energy. Now what does this have to do with its colour?

Well, electrons are able to absorb certain frequencies of electromagnetic radiation to get promoted to higher energy orbitals. These frequencies have a certain energy which correspond to the energy difference between different orbitals. Now most substances are only able to absorb frequencies of radiation which are outside the visible light spectrum, for example they might be able to absorb radiation which has a frequency of 300GhZ (that is infrared radiation). This means that it reflects all other types of radiation, including the full spectrum of visible light. So our eyes see a mixture of all the colours; red, green, blue, violet, etc. This is seen as white (this is why several organic compounds are white).

However transition metals are special in that the energy difference between the non-degenerate d orbitals correspond to the energy of radiation of the visible light spectrum. This means that when we look at the metal complex, we don't see the entire visible light spectrum, but only a part of it.

So for example, if the electrons in an octahedral metal complex are able to absorb green light and get promoted from the dyz orbital to the dz2 orbital, the compound will reflect all other colours except for green. Therefore by using the colour wheel, we can find the complementary colour of green which will be the colour of the compound, which is magneta.

Transition elements - NEET Notes - NEET

This explains why not all transition metal complexes are colourful. For example copper sulfate is a bright blue compound, however zinc sulfate on the hand is a white compound despite being a transition metal. The reason behind this is because zinc's d orbitals are completely filled up with electrons, meaning that it is not possible for any electron to make a d-> d transition as they are all filled up. Hence you might sometimes see zinc referred as not being a transition metal.

The document Transition elements - NEET Notes - NEET is a part of NEET category.
All you need of NEET at this link: NEET
Download as PDF

How to Prepare for NEET

Read our guide to prepare for NEET which is created by Toppers & the best Teachers

Download free EduRev App

Track your progress, build streaks, highlight & save important lessons and more!

Related Searches

Transition elements - NEET Notes - NEET

,

Transition elements - NEET Notes - NEET

,

Summary

,

ppt

,

pdf

,

Transition elements - NEET Notes - NEET

,

study material

,

practice quizzes

,

Viva Questions

,

past year papers

,

Previous Year Questions with Solutions

,

Extra Questions

,

Semester Notes

,

video lectures

,

mock tests for examination

,

MCQs

,

Exam

,

shortcuts and tricks

,

Sample Paper

,

Objective type Questions

,

Free

,

Important questions

;