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.

Q4.28:
What are inner transition elements? Decide which of the following atomic numbers are the atomic numbers of the inner transition elements : 29, 59, 74, 95, 102, 104.

Solution :

Definition of Inner Transition Elements

Inner transition elements, also known as the $f$-block elements, are those chemical elements in which the $f$-orbitals are progressively filled. These elements are characterized by the filling of $(n-2)f$ orbitals, where the penultimate energy level is involved. They are classified into two series:

  • Lanthanoids: Elements following Lanthanum ($Z=58$ to $71$), where the $4f$ orbitals are being filled.
  • Actinoids: Elements following Actinium ($Z=90$ to $103$), where the $5f$ orbitals are being filled.

[Per the IUPAC periodic table classification based on electronic configuration $ns^2 (n-1)d^{0-1} (n-2)f^{1-14}$]

Classification of Given Atomic Numbers

To determine if an element is an inner transition element, we compare its atomic number ($Z$) against the established ranges of the $f$-block series.

Atomic Number ($Z$) Electronic Configuration Classification
29 $[Ar] 3d^{10} 4s^1$ Transition element ($d$-block)
59 $[Xe] 4f^3 6s^2$ Inner transition element ($4f$ series)
74 $[Xe] 4f^{14} 5d^4 6s^2$ Transition element ($d$-block)
95 $[Rn] 5f^7 7s^2$ Inner transition element ($5f$ series)
102 $[Rn] 5f^{14} 7s^2$ Inner transition element ($5f$ series)
104 $[Rn] 5f^{14} 6d^2 7s^2$ Transition element ($d$-block)

Analysis of Results

By evaluating the electronic configurations:

  • $Z=29$ (Copper): The last electron enters the $3d$ orbital; hence it is a $d$-block transition element.
  • $Z=59$ (Praseodymium): Falls within the range $58-71$; it is a Lanthanoid (inner transition element).
  • $Z=74$ (Tungsten): The last electron enters the $5d$ orbital; it is a $d$-block transition element.
  • $Z=95$ (Americium): Falls within the range $90-103$; it is an Actinoid (inner transition element).
  • $Z=102$ (Nobelium): Falls within the range $90-103$; it is an Actinoid (inner transition element).
  • $Z=104$ (Rutherfordium): Follows the actinoids, where the $d$-orbital filling resumes; it is a $d$-block transition element.
Atomic Number Analysis for Inner Transition Elements: Inner Transition Ranges: Lanthanoids (58-71) & Actinoids (90-103) Identified Inner Transition Elements: 59, 95, 102

Final Solution: The atomic numbers of the inner transition elements from the provided list are 59, 95, and 102.


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

(105)
superTutorSuper Tutor
locationImg Arrah Chowk, Arrah
experience 11 yrs of Exp students 23 students
greenClock 815 hrs of classes completed
rsIcon 400 per hour
Experienced Chemistry Tutor | Class 11, 12, NEET, JEE | 14 Years Exp
Online Classes Online Classes

A Highly talented Chemistry teacher with excellent communication skills demonstrated by 11 years of teaching experience. Strong theoretical and good knowledge of Chemistry. A good Communication skills to maintain great relationship with students and ability to work well with others. You Can also watch me on my YouTube channel L.k.Soni Chemistry Classes. During live classes developed an approach where students can focus on the classes without any Distraction.

Sri Sai Kumar Ojjela

I had the opportunity to attend one-on-one Classes for class 12 CBSE Chemistry with him, and the experience was excellent. His way of explaining concepts is very clear, simple, and easy to understand. He makes sure that every doubt is addressed patiently and focuses not just on memorising reactions and formulas, but on developing a proper understanding of the concepts. I especially appreciated his exam-oriented approach, which makes difficult topics feel much more manageable and helps build confidence for the CBSE Board exams. He is very knowledgeable, supportive, and genuinely dedicated to his students. I would highly recommend his classes to any Class 12 CBSE Chemistry student looking for strong conceptual clarity and effective preparation.

Skills: Chemistry

(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

(36)
Top Tutor
locationImg Bhagalpur, Bhagalpur
experience 15 yrs of Exp students 3 students
greenClock 152 hrs of classes completed
rsIcon 600 per hour
Break The Term, Learn The Biology
Online Classes Online Classes

Biology like never before, every line of NCERT elaborating with a lot of mnemonics to make learning so easy

Skills: Biology

(10)
Top Tutor
locationImg Mulund West, Mumbai
experience 10 yrs of Exp students 1 student
greenClock 8 hrs of classes completed
rsIcon 700 per hour
YOUR SUCESS MY HAPPINESS YOUR ACHIEVEMENT MY DREAM
Online Classes Online Classes
homeTutions Student's Home

Experienced and dedicated Science educator with a strong background in teaching Physics, ,Maths to Grade 12 students. Skilled in creating engaging lesson plans aligned with CBSE/ICSE/State Board curricula, fostering scientific curiosity, and using modern teaching aids such as smart boards, simulations, and lab experiments. Proficient in classroom management, differentiated instruction, and continuous student assessment. Committed to promoting STEM education and preparing students for board exams and competitive entrance tests.

Skills: Mathematics , Physics

(26)
Top Tutor
locationImg Lake Town, Kolkata
experience 10 yrs of Exp students 2 students
greenClock 651 hrs of classes completed
rsIcon 650 per hour
Online English and Social studies tutor
Online Classes Online Classes

I am an educator with 9 years of teaching experience, specializing in English and Social Science for students from Class 1 to Class 12. Over the years, I have worked with learners from diverse academic backgrounds and age groups, helping them build a strong understanding of concepts while improving their overall academic performance and confidence. I hold a Bachelor of Arts (B.A.) degree and have also completed a TESOL certification. This professional training has strengthened my ability to teach English effectively, especially to students who are developing their language skills. It has helped me adopt learner-friendly techniques that focus on clarity, communication, and real-life usage of the language. My teaching experience spans primary, middle, and senior secondary levels, which allows me to adapt my teaching style according to the learner’s age and learning pace. In both English and Social Science, I focus on developing conceptual clarity, critical thinking, and answer-writing skills that are essential for school exams and overall academic growth. I follow a structured and well-planned lesson approach for every class. Each topic is taught step by step, starting from the basics and gradually moving to deeper understanding. I ensure that students are comfortable with the subject matter before progressing further, making learning less stressful and more effective. My classes are interactive and student-focused. I encourage students to ask questions, share their thoughts, and participate actively during lessons. I use practical examples, real-life connections, and discussions to make concepts easier to understand and more engaging, especially in subjects like Social Science. I conduct both online and offline classes and make use of PPTs and whiteboard-based teaching to support visual learning. My aim is to create a positive and supportive learning environment where students feel motivated, confident, and well-prepared to perform well academically while developing a genuine interest in English and Social Science.

Skills: English , Political Science and more
Also teaches: Class 8 Tuition, Class 10 Tuition and more

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 »