Periodic Classification of Elements: Students who want to know the periodic classification of element class 10 questions and answers can check this article. If you are working on NCERT Solution for Class 10 Science chapter 5 notes, it will help you to build a solid basis for the subject of science. NCERT Solution For class 10 science Chapter 5 periodic classification of elements will help you to pass UG competitive exam.
Going through this periodic class of elements NCERT activity solution will help you understand the theory behind each concept which in turn will help you to solve the question at the end of each topic and subtopic. Continue reading to know all about the periodic class of elements class 10 questions and answers.
NCERT Solutions for Class 10 Chapter 5 Periodic Classification of Elements
Before going into details about NCERT solutions for Class 10 Science Ch 5 Periodic Classification of Elements, here is a brief overview of the topics and subtopics of NCERT solutions for science ch 5 periodic periodic classification of Elements:
- The history of periodic classification of elements
- Early attempts at the classification of elements
- Mendeléev’s periodic table
- Making order out of chaos
- Modern periodic table
Chapter 5 Periodic Classification of Elements
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NCERT Solutions for Class 10 Chapter 5 Periodic Classification of Elements Textbook Question Answer
Question 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?
(a) The elements become less metallic in nature.
(b) The number of valence electrons increases.
(c) The atoms lose their electrons more easily.
(d) The oxides become more acidic.
Answer:
(c) The atoms lose their electrons more easily.
Question 2
Element X forms a chloride with the formula XCl2, which is solid with a high melting point. X would most likely be in the same group of the periodic table as
(a) Na
(b) Mg
(c) Al
(d) Si
Answer:
(b) Magnesium (Mg)
Question 3
Which element has
(a) two shells, both of which are completely filled with electrons?
(b) the electronic configuration 2, 8, 2?
(c) a total of three shells, with four electrons in its valence shell?
(d) a total of two shells with three electrons in its valence shell. v
(e) twice as many electrons in its second shell as in its first shell?
Answer:
(a) 2, 8 Neon
(b) Magnesium (Mg)
(c) (2, 8, 4) Silicon
(d) (2, 3) Boron
(e) (2, 4) Carbon
Question 4
(a) What properties do all elements in the same column of the Periodic Table as boron have in common?
(b) What properties do all elements in the same column of the Periodic Table . as fluorine have in common?
Answer:
(a) Elements in the same column or group as boron have a valency of three and have three valence electrons.
(b) Elements in the same column or group as fluorine form acidic oxides have seven electrons in their outermost shells and have a valency of one.
Question 5
An atom has electronic configurations 2, 8, 7.
(a) What is the atomic number of this element?
(b) To which of the following elements would it be chemically similar?
N (7), F (9), P (15), Ar (18)
Answer:
(a) The atomic number of the given element is 2 + 8 + 7(= 17).
(b) It would be chemically similar to fluorine [F(9)] because its electronic configuration is 2, 7.
Question 6
The positions of three elements A, B and C in the periodic table are shown below :
(a) State whether A is a metal or non-metal.
| Group 16 | Group 17 |
| – | – |
| – | A |
| – | – |
| B | C |
(b) State whether C is more reactive or less reactive than A.
(c) Will C be larger or smaller in size than B?
(d) Which type of ion, cation or anion, will be formed by element A?
Answer:
(a) Since the valency of group 17 elements is 1 and all these elements accept electrons, thus A is a non-metal.
(b) C is less reactive than A because as we move down in a group, the reactivity of non-metals increases.
(c) C is smaller in size than B because B and C both are related to the same period and the size decreases as one moves from left to right in a period.
(d) A will form an anion because it is a non-metal.
Question 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?
Answer:
Electronic configuration of nitrogen -2,5
Electronic configuration of phosphorus = 2, 8, 5
Nitrogen will be more electronegative because the outermost shell is nearer to the nucleus and therefore nucleus will attract electrons more strongly. In a group of the periodic table, electron attracting tendency decreases as we move from top to bottom.
Question 8
How does the electronic configuration of an atom relate to its position in the Modern Periodic Table?
Answer:
The modern periodic table is based on the atomic number and atomic number is directly related to the electronic configuration. One can find the group number and period number of an element on the basis of electronic configuration. For example, if an element has 1 or 2 electrons in its outermost shell, then it would belong to group 1 or group 2. And if it has 3 or more electrons in its outermost shell, then it would belong to group 10 4- the number of electrons in the outermost shell.
All the alkali metals have one electron in their outermost shell placed in group 1. Thus, all the group 2 elements have 2 electrons in their outermost shell. In group 15 elements, there are 5 electrons in their outermost shell. Similarly, the number of shells in an element indicates its period number. For example, the atomic number of magnesium is 12 and its electronic configuration is 2, 8, 2. Thus it is an element of 3rd period.
Question 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?
Answer:
The electronic configuration of elements with Atomic Number:
12 = (2, 8, 2)
19 = (2, 8, 8, 1)
20 = (2, 8, 8, 2)
21 = (2, 8, 9, 2)
38 = (2, 8, 18, 8, 2)
Elements with atomic number 12 i.e., magnesium (Mg) and 38 i.e., strontium (Sr) will have similar physical and chemical properties as elements with atomic number 20 i.e., calcium (Ca).
Question 10
Compare and contrast the arrangement of elements in Mendeleev’s Periodic Table and the Modern Periodic Table.
Answer:
| Mendeleev’s Periodic Table | Modern Periodic Table |
| (i) Elements are arranged in the order of increasing atomic mass. | (i) Elements are arranged in the order of increasing atomic number. |
| (ii) There are nine vertical columns called groups. | (ii) There are eighteen vertical columns called groups. |
| (iii) There is no place for noble gases. | (iii) Noble gases are placed on the right hand side of the table. |
| (iv) There is no place for isotopes. | (iii) Noble gases are placed on the right-hand side of the table. |
| (v) Transition elements are placed together in group VIII. | (v) Transition elements are placed in the middle of the long period (Group 3 to 12). |
Class 10 Periodic Classification of Elements MCQ with Answer
Question 1: Who is credited with creating the first periodic table?
A) Dmitri Mendeleev
B) Antoine Lavoisier
C) John Dalton
D) Niels Bohr
Answer: A) Dmitri Mendeleev
Question 2: How did Mendeleev arrange elements in his periodic table?
A) By atomic number
B) By atomic mass
C) By electronegativity
D) By electron configuration
Answer: B) By atomic mass
Question 3: How many periods are there in the modern periodic table?
A) 6
B) 7
C) 8
D) 9
Answer: B) 7
Question 4: Which group in the periodic table is known as the “Noble Gases”?
A) Group 1
B) Group 2
C) Group 7
D) Group 18
Answer: D) Group 18
Question 5: Elements in the same group have similar:
A) Atomic numbers
B) Atomic masses
C) Chemical properties
D) Physical properties
Answer: C) Chemical properties
Question 6: Which element has the symbol “O”?
A) Oxygen
B) Gold
C) Carbon
D) Hydrogen
Answer: A) Oxygen
Question 7: Which element is the most abundant in Earth’s crust?
A) Oxygen
B) Silicon
C) Carbon
D) Aluminum
Answer: B) Silicon
Question 8: Which element is represented by the symbol “Fe”?
A) Iron
B) Silver
C) Lead
D) Fluorine
Answer: A) Iron
Question 9: The element with atomic number 1 is:
A) Hydrogen
B) Helium
C) Lithium
D) Oxygen
Answer: A) Hydrogen
Question 10: Which group is known as the “Alkali Metals”?
A) Group 1
B) Group 2
C) Group 7
D) Group 18
Answer: A) Group 1
Question 11: Which element is a noble gas with atomic number 10?
A) Neon
B) Argon
C) Krypton
D) Xenon
Answer: B) Argon
Question 12: What is the chemical symbol for potassium?
A) K
B) Pt
C) Po
D) Pb
Answer: A) K
Question 13: Which element has the highest electronegativity?
A) Fluorine
B) Oxygen
C) Nitrogen
D) Carbon
Answer: A) Fluorine
Question 14: Which period contains the most elements?
A) 2nd period
B) 3rd period
C) 4th period
D) 5th period
Answer: C) 4th period
Question 15: Which group is known as the “Halogens”?
A) Group 1
B) Group 2
C) Group 7
D) Group 17
Answer: D) Group 17
Question 16: Which element has the highest atomic number?
A) Uranium
B) Plutonium
C) Radium
D) Osmium
Answer: A) Uranium
Question 17: Which element is essential for all living organisms?
A) Carbon
B) Oxygen
C) Nitrogen
D) Hydrogen
Answer: A) Carbon
Question 18: What is the chemical symbol for silver?
A) Ag
B) Au
C) Al
D) Si
Answer: A) Ag
Question 19: Which group is known as the “Transition Metals”?
A) Group 1
B) Group 2
C) Group 3-12
D) Group 17
Answer: C) Group 3-12
Question 20: Which element is commonly used in nuclear reactors as a fuel?
A) Uranium
B) Thorium
C) Plutonium
D) Neptunium
Answer: A) Uranium
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