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# NCERT Solutions for Class 10 Science Chapter 5 - Periodic Classification of Elements

## NCERT Solutions for Class 10 Science Chapter 5 - Free PDF

Last updated date: 25th Mar 2023
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Reason for inclusion of NCERT Solutions for Class 10 Science chapter 5 is to help students understand the classification of different elements in the periodic table. The classification varies on the basis of characteristics, which is whether elements on this table are metal or a non-metal. This chapter has been divided into various segments ranging from Dobereiner's table, Mendeleev's table and their advantages as well as limitations.

With various activities, this chapter aims to help students to enhance their process of learning by making it interesting. The student is also provided with the illustration of three types of the periodic table that make explanation of the topic a lot simpler.

Competitive Exams after 12th Science

## Access NCERT solutions for Class 10 Chemistry Chapter – 5 Periodic Classification of Elements

### Intext Exercise -1

1. Did Dobereiner’s Triads Also Exist in the Columns of Newlands’ Octaves? Compare and Find Out.

Ans: In the dobereiner's triads, the middle element atomic mass is equal to the average atomic mass of the first and third element. Only one Dobereiner’s triad exists in the columns of Newlands’ Octaves.

Newlands’ Octaves

 H Li Be B C N O F Na Mg AI Si P S CI K Ba Cr Ti Mn Fe

2. What Were the Limitations of Dobereiner’s Classification?

Ans: Limitation of Dobereiner’s Classification:

Only a few elements can be arranged in the Dobereiner's triads. It depends on their properties. F, Cl, Br will not show the triads but Cl , Br, I will show.

3. What Were the Limitations of Newlands’ Law of Octaves?

Ans: Limitations of Newlands’ law of octaves:

(i)  It was applicable up to lighter elements (Calcium only).

(ii)  The properties after calcium do not have any resemblance to the properties of the above element.

(iii) Co and Ni are transition elements but they were placed in the group of F, Cl.

(iv) Iron properties are similar to the cobalt and nickel but placed in different columns.

### Intext Exercise -2

1. Use Mendeleev’s Periodic Table To Predict the Formula for the Oxides of the Following Elements: K, C, Al, Si, Ba.

Ans: Potassium is in group 1. The oxide will be ${{K}_{2}}O$ .

Carbon is in group 4. The oxide will be $C{{O}_{2}}$ .

Aluminium is in group 3. The oxide will be $A{{l}_{2}}{{O}_{3}}$ .

Silicon is in group 4. The oxide will be $Si{{O}_{2}}$ .

Barium is in group 2. The oxide will be $BaO$ .

2. Besides Gallium, Which Other Elements Have Since Been Discovered That Were Left by Mendeleev in His Periodic Table? (Any Two)

Ans: Gallium(Ga) and Scandium(Sc)

3. What Were the Criteria Used by Mendeleev in Creating His Periodic Table?

Ans: Mendeleev’s periodic table was based on the atomic masses of the elements. The properties of the elements are the periodic function of their atomic masses. Elements are arranged in the increasing atomic mass and their properties reoccur after regular intervals.

4.

a) Lithium, Sodium, Potassium Are All Metals That React With Water To Liberate Hydrogen Gas. Is There Any Similarity in the Atoms of These Elements?

Ans: Yes, all the three elements lithium, sodium, and potassium have one electron in the valence shells.

b) Helium is an Unreactive Gas and Neon is a Gas of Extremely Low Reactivity. What, if Anything, Do Their Atoms Have in Common?

Ans: Helium (He) and neon (Ne) are inert gas. Their outermost shells are completely filled. Helium has a duplet in its K shell, while neon has an octet in its K, L shell.

5. In the Modern Periodic Table, Which are the Metals Among the First Ten Elements?

Ans: Lithium (Li) and beryllium (Be) are metals among the first ten elements.

6. By Considering Their Position in the Periodic Table, Which One of the Following Elements Would You Expect To Have Maximum Metallic Characteristic? Ga, GE, As, Se and Be.

Ans: Be and Ga are expected to be more metallic but Metallic character increases when we go from top to bottom. Due to its larger size for gallium, it is the most metallic among the given elements.

### NCERT Exercises

1. Which of the following statements is not a correct statement about the trends when going from left to right across the periods of the periodic Table?

1. The elements become less metallic in nature.

2. The number of valence electrons increases.

3. The atoms lose their electrons more easily.

4. The oxides become more acidic.

Ans: (c) The atoms lose their electrons more easily.

(In this period, the atom's size decreases so it is difficult to lose their electrons.)

2. Element X forms a Chloride with the Formula $XC{{l}_{2}}$ , Which is a Solid with a High Melting Point. X would most likely be in the same group of the Periodic Table as

a) Na

Ans: Valency of X in the given compound is 2. But Na is in group 1 in the periodic table. Hence, it does not form the given compound with chloride.

b) Mg

Ans: Valency of X in the given compound is 2. Mg is in the group 2 in the periodic table.

c) Al

Ans: Valency of X in the given compound is 2. But Al is in the group 3A in the periodic table. Hence, it does not form the given compound with chloride.

### d) Si

Ans: Valency of X in the given compound is 2. But the valence of Si is 4. Hence, it does not form the given compound with chloride.

3. Which Element has

a) Two shells, both of which are completely filled with electrons?

Ans: Neon has two shells, both of which are completely filled with Electrons

b) The Electronic Configuration 2, 8, 2?

Ans: Magnesium electronic configuration is 2, 8, 2.

c) A Total of Three Shells, With Four Electrons in its Valence Shell?

Ans: Silicon has three shells, with four electrons in its valence shell

d) A total of two shells, with three electrons in its valence shell?

Ans: Boron has two shells, with three electrons in its valence shell

### e) Twice as many electrons in its second shell as in its first shell?

Ans: Carbon has twice as many electrons in its second shell as in its first shell.

4.

a) What property do all elements in the same column of the Periodic Table as boron have in common?

Ans: All the elements have the same number of valence electrons and the valency is equal to 3.

b) What property do all elements in the same column of the Periodic Table as fluorine have in common?

Ans: All the elements have the same number of valence electrons and they all have valency equal to 1.

5. An Atom Has Electronic Configuration 2, 8, 7.

a) What is the atomic number of this element?

Ans: Atomic number of the given configuration is 17.

b) To which of the following elements would it be chemically similar? (Atomic numbers are given in parentheses.)

N(7) F(9) P(15) Ar(18)

Ans: Fluorine electronic configuration is 2, 7. same number of valence    electrons in the outermost shell.

6. The Position of Three Elements A, B and C in the Periodic Table are Shown Below

 Group 16 Group 17 - - - A - - B C

a) State whether A is a metal or nonmetal.

Ans: A is a non-metal.

b) State whether C is more reactive or less reactive than A.

Ans: C is less reactive than A. Reactivity decreases down the group in halogens.

c) Will C be larger or smaller in size than B?

Ans: When we move from left to right, the atomic size decreases so C is smaller than B.

d) Which type of ion, cation or anion, will be formed by element A?

Ans: A is in group 17 so the valence electrons will be 7. It would form an anion and accept an electron to complete the octet.

7. Nitrogen (atomic number 7) and Phosphorus (atomic number 15) Belong to Group 15 of the Periodic Table. Write the Electronic Configuration of These Two Elements. Which of These Will Be More Electronegative? Why?

Ans: The electronic configuration of the group 15 elements.

### 2, 8, 5

Electronegativity is the tendency of an atom of an element in a molecule to attract the shared pair of electrons present between bonded atoms towards itself. When we move from left to right electronegativity increases and when we move from top to bottom the electronegativity decreases. In case of group 15, the electronegativity decreases. Nitrogen is more electronegative than phosphorus.

8. How Does the Electronic Configuration of an Atom Relate to its Position in the Modern Periodic Table?

Ans: In the modern periodic table, the period number of an element is equal to the number of shells in its atom. The group number of an element having up to two valence electrons is equal to the number of valence electrons. If more than two valence electrons is equal to the number of valence electrons plus 10.

9. In the Modern Periodic Table, Calcium (Atomic Number 20) is Surrounded by Elements With Atomic Numbers 12, 19, 21, and 38. Which of These Have Physical and Chemical Properties Resembling Calcium?

Ans:

 Atomic number Electronic configuration Calcium(20) 2, 8, 8, 2 12 2, 8, 2 19 2, 8, 8, 1 21 2,8, 8, 3 38 2, 8, 8, 18, 2

Elements with atomic number 12 and 38 have the same chemical properties as that of calcium. Because both of them have the same number of valence electrons.

10. Compare and Contrast the Arrangement of Elements in Mendeleev’s Periodic Table and the Modern Periodic Table.

Ans:

 Mendeleev’s periodic Table Modern Periodic Table 1. Properties of the elements are periodic function of their increasing atomic mass Properties of the elements are periodic function of their increasing atomic numbers 2. There are a total 7 groups (columns) and 6 periods (rows) There are total 18 groups (columns) and 7 periods (rows) 3. Elements having similar properties were placed directly under one another Elements having the same valence shell are present in the same period while elements having the same number of valence electrons are present in the same group 4. Position of the hydrogen is not fixed. Hydrogen is placed in 1st group 5. No difference in the position of metals and non-metals. Metals are present at the left side and non-metals are present at the right hand side. 6. This table is given by Mendeleev. This table is given by Henry Moseley.

## NCERT Solutions for Class 10 Science Chapter 5 - Periodic Classification of Elements

Students who are looking for NCERT Solutions for Class 10 Science Chapter 5 - Periodic Classification of Elements PDF can opt for Upcoming Exams and also You can Find the Solutions of All the Science Chapters below.

### NCERT Study Resources for Class 10 Science

Ace your Science exam in Class 10 boards by preparing from the comprehensive study resources provided by Vedantu. Click on the links below and download the free PDF.

### NCERT Solutions for Class 10 Science Chapter 5 – Free PDF Download

By referring to the 5 Science class 10 solutions available for NCERT, the students are able to avail a simpler procedure of learning. It consists of various to the point question and answers, followed by proper explanations of different subtopics. This solution is what students can avail when they are trying to comprehend the basic concept behind this chapter.

This primary knowledge will prove to be useful when a student moves on towards later years of their education. To understand chemistry as a subject, having a clear concept about elements on the periodic table is necessary.

### Important Subtopics Covered in Class 10 Chapter 5

• Early Attempts At the Classification of Elements

• Mendeleev’s Periodic Table

• The Modern Periodic Table

### Points Discussed in Chapter 5

• Elements are classed according to how comparable their characteristics are. Newlands devised the Law of Octaves after Döbereiner divided the elements into triads.

• The elements were organized by Mendeléev in ascending order of their atomic weights and chemical characteristics.

• On the basis of gaps in his Periodic Table, Mendeléev even anticipated the presence of several yet-to-be-discovered elements.

• When the elements were organized in order of increasing atomic number, a fundamental attribute of the element identified by Moseley, anomalies in the arrangement of elements based on rising atomic mass could be addressed.

• The Modern Periodic Table divides elements into 18 vertical columns called groups and seven horizontal rows named periods.

• The periodicity of features such as atomic size, valency or combining capacity, and metallic and non-metallic character may be seen in this arrangement.

### Benefits of NCERT Class 10 Solutions

1. The the NCERT Solutions are created keeping in mind the Class 10 CBSE Syllabus and chapter-wise mark distribution.

2. Students might have a better understanding of subjects by using elaborate answers.

3. Step-by-step explanations are provided for the numbers in this chapter.

4. The use of straightforward and logical language boosts students' confidence.

5. Wherever possible, pupils are given visual representations to help them absorb subjects more quickly.

### Class 10 Science Chapter 5 - Periodic Classification of Elements Weightage 2021-22

The term 2 CBSE Class 10 Science exam is of 40 marks, with 10 marks on internal assessment, just like the weightage of the term 1 Science exam. Class 10 Science Chapter 5 Periodic Classification of Elements contributes to 10% of the exam. Here is the topic-wise weightage of the chapter.

 Topics Number and Type of Questions Early Attempts at the Classification of Elements 3 (2 long, 1 short) Mendeleev’s Periodic Table 4 (1 long, 3 short) The Modern Periodic Table 6 (1 long, 5 short) Exercise Solutions 10 (2 long, 8 short)

### NCERT Solutions for Class 10 Science Chapter 5 Exercises

• Exercise 5.1 – Early Attempts at the Classification of Tables

In this segment of chapter 5 science Class 10, students will learn how elements were classified in the periodic table based on their properties. These elements were segregated from one another on the basis of whether they were gases, metals or non-metals.

• Exercise 5.1.1 – Dobereiner's Triads

A German chemist, known to all as Johann Wolfgang Dobereiner, had attempted to group elements based on their properties. Formation of these groups was known as triads.

• Exercise 5.1.2 – Newland's Laws of Octaves

In this section of the periodic classification of elements in Class 10 solutions, learn about how in this table, every eighth element displays properties that are similar to the first one. This law may appear in the examination so students will need to memorise it thoroughly.

• Exercise 5.2 – Mendeleev's Periodic Table

In this section of the periodic classification of elements of class 10 NCERT solutions, an introduction to Mendeleev's periodic table has been provided. In this table, elements were arranged, based on their increasing atomic masses.

• Exercise 5.2.1 – Achievements of Mendeleev's Periodic Table

This periodic table present in Class 10 Science Chapter 5 NCERT solutions was able to predict the existence of certain elements that back then had not been discovered back then. These elements include Germanium (Ge), Gallium (Ga) and Scandium (Sc).

• Exercise 5.2.2 – Limitations of Mendeleev's Periodic Table

In this periodic table present in Ch 5 Science Class 10 NCERT solutions, there is no explanation found about Isotopes. Hydrogen in this table does not have a fixed position, and Mendeleev also fails to provide any explanation regarding the atomic masses being in the wrong order for some elements.

• Exercise 5.3 – Modern Periodic Table

Elements present in this table of Class 10 Periodic Classification of Elements solutions have been arranged on the basis of their increasing atomic masses. Students will need to learn the order of the elements in this periodic table for their examinations.

• Exercise 5.3.1 – Position of Elements in the Modern Periodic Table

This modern periodic table that we find in Class 10 Science Ch 5 solutions, consists of 7 periods and 18 groups. Elements in a period are set on the basis of the maximum number of electrons present.

• Exercise 5.3.2 – Trends in the Modern Periodic Table

There are different trends in the modern periodic table that have been noticed, which students will learn about in this section. Electronegativity, electron affinity, metallic character, atomic radius, etc. are some of the many trends.

### Benefits of NCERT Solutions for Class 10 Science Chapter 5

Here are some of the benefits of availing Class 10th Science chapter 5 solutions from Vedantu -

• The solution is framed in a question and answer format to ease the process of learning.

• All questions come with accurate solutions

• Areas of uttermost importance that might appear in examinations are covered.

• Help in building the foundation for a student's knowledge about the subject.

• Solution is constructed in a step by step manner to help a student understand easily.

With the help of NCERT solutions for Class 10 Science Chapter 5 Periodic Classification of Elements from Vedantu, score well in examinations.

Since you have read why solving NCERT Solutions for Class 10 Science Chapter 5 by Vedantu is important, we hope that you will go through this PDF diligently. Also, since you have gone through the chapter’s gist and topic-wise weightage provided in the article, you know how to prepare your revision strategy. If you find this chapter rather difficult, you can refer to Vedantu’s revision notes, important questions and other study resources for smooth exam preparation.

## FAQs on NCERT Solutions for Class 10 Science Chapter 5 - Periodic Classification of Elements

1. What is there in for NCERT solutions for Class 10 Science chapter 5?

This chapter, Periodic Classification of Elements, includes exercises that talks about three different periodic tables. We first are informed about classification of elements in terms of their properties in the beginning. It then moves on to explain to students exactly what the Dobereiner's triad is and the concept behind it.

Students also learn about the Newland's Law of Octaves that later was removed and Mendeleev's periodic table was introduced. This chapter finally proceeds to explain the modern periodic table and the classification of the elements present on it.

2. What are the new topics to be learnt in chapter 5 class 10 Science?

The new topics to be learnt in Chapter 5 of NCERT Solutions for Class 10 Science are:

• Newlands' Law Of Octaves.

• Mendeleev's Periodic Table: Its merits and demerits.

• The Modern Periodic Table.

• Position of Elements in the Modern Periodic Table.

• Trends in the Modern Periodic Table.

As a practical subject, you must have a clear concept about elements on the periodic table to understand chemistry.

3. Why should I refer to the NCERT Solutions for Class 10 Science Chapter 5?

Students can benefit from a simplified learning method by referring to the Science Chapter 5 of Class 10 answers available on the Vedantu website and on the Vedantu app at free of cost. Vedantu offers NCERT Solutions for Class 10 Science Chapter 5. It is made up of a series of short, to-the-point questions and answers, followed by thorough explanations of numerous subtopics. These are the high-quality solutions written by subject matter experts that students can refer to if they are having trouble grasping the core concept of this chapter.

4. What concepts can I learn using the NCERT Solutions for Class 10?

The inclusion of NCERT Solutions for Class 10 Science Chapter 5 aims to aid students in understanding the periodic table's classification of different elements. The categorization is based on features, such as whether or not the components in this table are metal or nonmetal. This chapter is separated into sections that cover everything from Dobereiner's Table through Mendeleev's Table, as well as its benefits and drawbacks. You can refer to Vedantu’s NCERT Solutions for Class 10 Science Chapter 5 to understand the concepts. These solutions will not only help students with board exams but also in various competitive exams.

5. What is the basic concept of Exercise 5.1 in Chapter 5 Science of Class 10?

Students will study how elements were categorised in the periodic table based on their characteristics in this part of Chapter 5 Science Class 10. Depending on whether they were gases, metals, or non-metals, these elements were separated from one another.

6. What is Exercise 5.2 of Chapter 5 Science of Class 10 about?

An introduction to Mendeleev's periodic table is offered in this portion of the periodic classification of elements of Class 10 NCERT answers. The elements were ordered in this table according to their increasing atomic masses. This is an important topic and questions might come from this portion in your exams. Download Vedantu’s NCERT Solutions for Class 10 Science Chapter 5 free of cost to learn the chapter better and score high marks in exams.