default_background
✕

Find the best tutors and institutes for Class 12 Tuition

Find Best Class 12 Tuition

Please select a Category.

Please select a Locality.

No matching category found.

No matching Locality found.

Q4.35 (ii):
Compare the general characteristics of the first series of the transition metals with those of the second and third series metals in the respective vertical columns. Give special emphasis on the following points: (ii) oxidation states

Solution :

Step 1: Theoretical Foundation of Oxidation States in Transition Metals

The oxidation states of transition metals are governed by the availability of $(n-1)d$ and $ns$ electrons for bonding. In the first transition series ($3d$), the energy gap between $3d$ and $4s$ orbitals is relatively small, allowing for a wide range of variable oxidation states. In contrast, as we descend to the second ($4d$) and third ($5d$) series, the $(n-1)d$ orbitals become more spatially extended and higher in energy relative to the $ns$ orbitals, significantly altering their stability and participation in chemical bonding [Per the Slater's Rules and effective nuclear charge trends].

Step 2: Comparative Analysis of Oxidation State Stability

The stability of higher oxidation states increases down a group. This is the inverse of the behavior observed in $p$-block elements. The following table summarizes the key distinctions:

Feature First Series ($3d$) Second ($4d$) & Third ($5d$) Series
Max Oxidation State Generally lower Generally higher
Stability of High States Less stable Highly stable
Example $Ti(IV)$ is most stable $W(VI)$, $Re(VII)$, $Os(VIII)$ are stable

Step 3: Justification of Periodic Trends

  • Ionization Enthalpies: The lower series ($4d, 5d$) exhibit lower ionization enthalpies compared to the $3d$ series due to the increased size of the atoms and better shielding provided by the $4f$ and $5d$ electrons [Per the Lanthanide Contraction effect].
  • Bond Energy: Metals in the $4d$ and $5d$ series form much stronger bonds with ligands than their $3d$ counterparts. Consequently, the energy released upon forming a high oxidation state compound is sufficient to compensate for the ionization energy required to remove multiple electrons.
  • Example - Group 6: In Group 6, Chromium ($3d$) typically exhibits $+3$ or $+6$ oxidation states, but the $+6$ state in $CrO_4^{2-}$ is a strong oxidizing agent. In contrast, Molybdenum ($4d$) and Tungsten ($5d$) form stable compounds like $MoO_3$ and $WO_3$ where the $+6$ state is significantly more stable and less prone to reduction.

Visual Representation of d-Orbital Participation

Energy Level / Stability Energy 3d Series 4d Series 5d Series

Conclusion on Oxidation Trends

While the first series ($3d$) transition metals rely on the involvement of $3d$ electrons to achieve variable oxidation states, the compounds are often unstable in their highest oxidation states. The $4d$ and $5d$ series show a marked preference for higher oxidation states due to the increased spatial extent of the $d$-orbitals, which facilitates stronger covalent character in metal-ligand bonds. This trend ensures that for any given group, the stability of high oxidation states increases as: $3d < 4d \approx 5d$.

Final Solution: The stability of higher oxidation states increases down a group in the d-block. Specifically, while the first series ($3d$) metals show variable oxidation states with relatively unstable higher states, the second ($4d$) and third ($5d$) series metals form highly stable compounds in their maximum possible oxidation states (e.g., $OsO_4$ in $+8$, $WO_3$ in $+6$) due to lower ionization enthalpies and stronger metal-ligand bond formation.


More Questions from Class 12 Chemistry The d- and f-Block Elements Exercises


CBSE Solutions for Class 12 Chemistry The d- and f-Block Elements


Chapters in CBSE - Class 12 Chemistry


Top Tutors who teach The d- and f-Block Elements

(22)
superTutorSuper Tutor
locationImg Malkajgiri D.D.Colony, Hyderabad
experience 20 yrs of Exp students 21 students
greenClock 1592 hrs of classes completed
rsIcon 500 per hour
Dedicated Math teacher 32+ experience
Online Classes Online Classes

32+ years of teaching. Conducted online classes for more than 10 years. Prepared question papers and materials. Teaching students preparing for IIT, VITEE, COMEDK and other entrance examinations. Teach problems from various other authors, other state books and train students for their examinations. Conducted weekly quizzes and unit wise tests. Also conducted mock examinations before the board exam

Skills: Mathematics , Applied Mathematics and more
Also teaches: Class 11 Tuition, Class 10 Tuition and more

(20)
superTutorSuper Tutor
locationImg Mathara, Kozhikode
experience 12 yrs of Exp students 23 students
greenClock 919 hrs of classes completed
rsIcon 700 per hour
Experienced and certified Physics mentor from Kerala.
Online Classes Online Classes

I have been teaching Physics for the past 18 years and I am passionate about making Physics simple, conceptual and accessible for every student. My academic background includes M.Sc. in Physics, B.Ed., SET, AWES CSB PGT Physics, and CTET qualifications. I worked as PGT Physics at APS Nasirabad, APS Roorkee, Kendriya Vidyalaya Banar, Rajasthan and Assistant Lecturer of Physics in Aakash Institute. My online classes are highly structured, interactive, and tailored to meet the individual comfort and academic requirements of students.

Sani Kazi

I had a good experience with Prajeesha Ma'am. She gives clear explanation and questions of all sorts including PYQs to help students understand practice the concept very well.

Skills: Physics
Also teaches: Chess Coaching, NEET-UG Coaching and more

Kalaiselvi Class 12 Tuition trainer in Chennai
(28)
Top Tutor
locationImg Anna Nagar Mullai Nagar, Chennai
experience 9 yrs of Exp students 10 students
greenClock 415 hrs of classes completed
rsIcon 600 per hour
Online Mathematics tutor with 8 years experience(Online Classes for 10th to 12th)
Online Classes Online Classes

Hi, I'm Kalaiselvi, an M.Sc. Mathematics graduate with 9 years of experience in one-on-one online Maths tutoring. I specialize in teaching Classes 10, 11, and 12 for CBSE and Tamil Nadu State Board. My classes are conducted in both English and Tamil (bilingual), making concepts easy to understand. I focus on concept clarity, problem-solving, regular practice, and exam preparation, with personalized attention for every student.

K Suhasini

Math class was interesting at times, especially when the topics were explained with real-life examples.The mix of learning and problem-solving made the experience enjoyable and not just about memorizing formulas.This made math feel more flexible and creative rather than just following one method.

Skills: Mathematics

(37)
Top Tutor
locationImg West Jafferkhanpet, Chennai
experience 7 yrs of Exp students 12 students
greenClock 171 hrs of classes completed
rsIcon 600 per hour
Experienced and Certified Computer Science Python Tutor in Chennai for CLASS 12 & CLASS 11 CBSE
Online Classes Online Classes
homeTutions Student's Home
regularClasses Tutor's home

I am an experienced, qualified teacher and tutor with over 8 years of experience in teaching COMPUTER SCIECE subject exclusively for 11th and 12th (CBSE Board). I will cover complete CBSE NCERT Computer Science syllabus such as Python, Database Management and Computer Networks. I guide my students to do Programs by themselves and help them to find the logics of the programs in a easy manner and make them to understand the subject to core. Passionate about solving and writing programs and over the years I have helped my students overcome their fear of Computer Science programs. I teach the subject from scratch, so anyone who is afraid of subject and want to give a start can contact me.

Mubashir

He is very polite, patient and teaches very well. I would definitely recommend this tutor to other students looking for quality guidance.

Skills: Computer Science

(22)
Top Tutor
locationImg Sakinaka East, Mumbai
experience 5 yrs of Exp students 1 student
greenClock 47 hrs of classes completed
rsIcon 1500 per hour
Physics Lecturer with 5 years of experience in IIT-JEE & NEET, CBSE, HSC
Online Classes Online Classes
homeTutions Student's Home

PHYSICS TUTORING WITH A PHYSICS EXPERT: STRATEGIES THAT MAKE SENSE FOR YOU! ABOUT SUBJECT Students will receive personalized instruction from a Physics expert. We will use the most successfully proven teaching techniques, and will also create brand new strategies to fit the students' individual needs. DESCRIPTION In this private tutoring session, I will thoroughly explain whatever Physics concepts you are currently struggling with, or we can learn new topics if you want to get ahead. I have taught Physics for over 5 years, and I am passionate about helping students understand it. Just name a topic of Physics (Mechanics, Heat, Wave, Electromagnetism, Modern Physics), and I will explain it in a way that makes the most sense to you. Then we will complete practice problems together to make sure you feel confident moving forward. I will also develop individualized strategies for you to use moving forward. Don't be surprised if I get really excited about the information you're learning - PHYSICS MAKES ME HAPPY AND I HOPE MY ENJOYMENT OF THE SUBJECT MAKES IT LESS INTIMIDATING TO YOU. Physics isn't your enemy; you just need someone to explain it in a way you understand. Please let me! Teacher Expertise I have a B.Tech degree in Computer Science and I have been teaching Physics exclusively for the past 5 years. ABOUT ME I am a Physics lover through and through! I've always said “PHYSICS DOESN'T HAVE TO BE HARD; YOU JUST NEED SOMEONE TO EXPLAIN IT IN A WAY YOU UNDERSTAND." I can do that! I’m passionate about helping students gain confidence and mastery in Physics. Physics is my favorite subjects, so you'll see me get really excited about them! When I teach, I customize my strategies to fit your individual needs, and I have so many tricks up my sleeve for teaching Physics concepts, I can always find a method that works for you. And of course, it is especially important to me to make sure every student feels safe to make mistakes in my class – we celebrate mistakes! The only way to master Physics is to learn from your mistakes! I've taught JEE & NEET Physics online for 5 years and in coaching industry for over 5 years. It's a real pleasure to help students achieve their goals in IIT-JEE & NEET.

Skills: Physics , Computer Science

Other Subjects in CBSE - Class 12

Worksheet Icon

Download free CBSE - Class 12 Chemistry The d- and f-Block Elements Exercises worksheets

Download Now

Find Best Class 12 Tuition ?

Find Now »