default_background
✕

Find the best tutors and institutes for Class 11 Tuition

Find Best Class 11 Tuition

Please select a Category.

Please select a Locality.

No matching category found.

No matching Locality found.

Q3.4:
On the basis of quantum numbers, justify that the sixth period of the periodic table should have 32 elements.

Solution :

Step 1: Theoretical Basis of Periodicity

The periodic table is constructed based on the filling of subshells according to the Aufbau Principle, the Pauli Exclusion Principle, and Hund’s Rule. A new period begins when a new principal quantum number ($n$) starts filling, and a period ends when the corresponding outer shell ($ns$ and $np$) is completely filled.

Step 2: Identifying the Orbitals for the Sixth Period

For the sixth period, the principal quantum number $n = 6$. The subshells that are filled during this period are dictated by the $(n+l)$ rule, which determines the order of energy levels:

  • The $6s$ orbital ($n=6, l=0$)
  • The $4f$ orbital ($n=4, l=3$)
  • The $5d$ orbital ($n=5, l=2$)
  • The $6p$ orbital ($n=6, l=1$)

[Per the Aufbau Principle, electrons occupy orbitals in order of increasing energy: $6s < 4f < 5d < 6p$.]

Step 3: Calculating Electron Capacities for Each Subshell

The capacity of any subshell to hold electrons is given by the formula $2(2l + 1)$, where $l$ is the azimuthal quantum number.

Subshell Azimuthal Quantum Number ($l$) Number of Orbitals ($2l+1$) Electron Capacity $2(2l+1)$
$6s$ $0$ $1$ $2$
$4f$ $3$ $7$ $14$
$5d$ $2$ $5$ $10$
$6p$ $1$ $3$ $6$

Step 4: Summation and Conclusion

The total number of elements in a period corresponds to the total number of electrons that can be accommodated in the subshells being filled. Summing these values:

$\text{Total Electrons} = (\text{Capacity of } 6s) + (\text{Capacity of } 4f) + (\text{Capacity of } 5d) + (\text{Capacity of } 6p)$

$\text{Total Electrons} = 2 + 14 + 10 + 6 = 32$

6s (2) + 4f (14) + 5d (10) + 6p (6) = 32 Orbitals Total Period Capacity: 32 Elements

Since each element is characterized by a unique electronic configuration (Pauli Exclusion Principle), the filling of these 16 specific orbitals accounts for exactly 32 distinct quantum states, which corresponds to 32 elements.

Final Solution: The sixth period contains 32 elements because the cumulative capacity of the $6s$, $4f$, $5d$, and $6p$ subshells is $2 + 14 + 10 + 6 = 32$ electrons.


More Questions from Class 11 Chemistry Classification of Elements and Periodicity in Properties EXERCISES


CBSE Solutions for Class 11 Chemistry Classification of Elements and Periodicity in Properties


Chapters in CBSE - Class 11 Chemistry


Top Tutors who teach Classification of Elements and Periodicity in Properties

(61)
Top Tutor
locationImg HMT Estate 2nd Stage, Bangalore
experience 20 yrs of Exp students 32 students
greenClock 2767 hrs of classes completed
rsIcon 550 per hour
I am a teaching professional with 15 years of experience and over 2500 hours of online teaching
Online Classes Online Classes

I am a teacher. Teaching chemistry for the past 20+ years. I also have some experience in research in applied chemistry. I have a masters degree in chemistry and a bachelors degree in education. In addition to teaching I have experience in school administration and content development. My key skills are to train the students for various competitive exams like JEE, NEET, BITSAT, CET.

Srikar Kalluri

She is patient , understanding and then times the classes as per the students requirements. Gentle and slow. The right kind of teacher for chemistry subject.

Skills: Chemistry

(27)
Top Tutor
locationImg Laxmi Vihar, Hisar
experience 4 yrs of Exp students 3 students
greenClock 267 hrs of classes completed
rsIcon 800 per hour
A mathematics enthusiast, B.Sc. (Maths), M.Sc (Pure Maths) PhD Maths (Pursuing).
Online Classes Online Classes

I've taught Mathematics of class 11th and 12th in an academy for 2 years. And now teaching on UrbanPro from last 4 years. I focus on letting the student reach the deepest level of concept and then do problems of reference books like RD Sharma and others. My main target is to make student learn how to approach a question so that he can do by himself should he face any new problem.

Karthik S

Saurabh sir is a good teacher, and is clearly very knowledgeable in Mathematics. He takes time to clarify each and every concept, and caters to any schedule requirements, etc. The classes are interactive and super helpful.

Skills: Mathematics , Applied Mathematics

locationImg Garia, Kolkata
experience 4 yrs of Exp students 1 student
greenClock 20 hrs of classes completed
rsIcon 500 per hour
A college student with 1 year experience in private tution
Online Classes Online Classes
homeTutions Student's Home
regularClasses Tutor's home

I can teach and make students understand concepts with fun. So they doesn't feel bored in the class

Skills: Economics , Accounts and more

(23)
Top Tutor
locationImg Shastri Colony, Panipat
experience 7 yrs of Exp students 17 students
greenClock 898 hrs of classes completed
rsIcon 500 per hour
ONLINE TUTOR FOR PHYSICS SUBJECT
Online Classes Online Classes
regularClasses Tutor's home

Experienced Educator specializing in Physics. I have entered into the field of teaching and started to make and feel physics easy and exciting by the students and also make students to crack the most of the competitive examinations by which I will make them achieve their goals in future. I have been successfully training students from class 10t,11th and 12th for the last 11 years in Physics, along with JEE Mains & Advanced, NEET exam preparation. With 11 years of teaching experience and a background in Unacademy ( Doubt Solving Expert) and Filo Edutech Platform, I provide comprehensive coaching for students preparing for board exams and competitive tests.

Bhaskar

A good, kind and a patient teacher, who creates a positive and a supportive environment for her students.

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

(13)
Top Tutor
locationImg Ramachandra Puram, Hyderabad
experience 10 yrs of Exp students 4 students
greenClock 255 hrs of classes completed
rsIcon 400 per hour
Accountancy for Class 11 & 12 | Strong Basics | Smart Practice | Better Scores
Online Classes Online Classes
homeTutions Student's Home

I am an experienced academic teacher and tutor, specialised in teaching Accountancy to Class 11 students. My teaching approach focuses on building strong fundamentals, simplifying complex chapters and explaining practical problems step by step and making learning engaging and effective. Through interactive teaching, personalised attention and exam-oriented practice, I help students prepare effectively and perform well in their exams.

Nakshatra reddy

He teaches really well so that we can understand the concept.His concept understanding is very good.

Skills: Accountancy , Accounting and more
Also teaches: Class 12 Tuition, CA Coaching

Other Subjects in CBSE - Class 11

Worksheet Icon

Download free CBSE - Class 11 Chemistry Classification of Elements and Periodicity in Properties EXERCISES worksheets

Download Now

Find Best Class 11 Tuition ?

Find Now »