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NCERT solutions Science Class 10 chapter 5 Periodic Classification of Elements

Chapters

NCERT Science Class 10

Science Textbook for Class 10

Chapter 5 - Periodic Classification of Elements

Page 81

Did Dobereiner’s triads also exist in the columns of Newlands’ Octaves? Compare and find out.

Q 1 | Page 81

What were the limitations of Newlands’ Law of Octaves?

Q 2 | Page 81

Page 85

 Use Mendeleev’s Periodic Table to predict the formulae for the oxides of the following elements:
K, C, Al, Si, Ba.

Q 1 | Page 85

Besides gallium, which other elements have since been discovered that were left by Mendeleev in his Periodic Table? (any two)

Q 2 | Page 85

What were the criteria used by Mendeleev in creating his Periodic Table?

Q 3 | Page 85

Why do you think the noble gases are placed in a separate group?

Q 4 | Page 85

Pages 90 - 91

How could the Modern Periodic Table remove various anomalies of Mendeleev’s Periodic Table?

Q 1 | Page 90

Name two elements you would expect to show chemical reactions similar to magnesium. What is the basis for your choice?

Q 2 | Page 90

Name three elements that have a single electron in their outermost shells.

Q 3.1 | Page 91

 Name two elements that have two electrons in their outermost shells.

Q 3.2 | Page 91

Name three elements with filled outermost shells.

Q 3.3 | Page 91

Lithium, sodium, potassium are all metals that react with water to liberate hydrogen gas. Is there any similarity in the atoms of these elements?

Q 4.1 | Page 91

Helium is an unreactive gas and neon is a gas of extremely low reactivity. What, if anything, do their atoms have in common?

Q 4.2 | Page 91

In the Modern Periodic Table, which are the metals among the first ten elements?

Q 5 | Page 91

 By considering their position in the Periodic Table, which one of the following elements would you expect to have maximum metallic characteristic?

Q 6 | Page 91

Pages 91 - 92

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

Q 1 | Page 91

Element X forms a chloride with the formula XCl2, 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

(b) Mg

(c) Al

(d) Si
Q 2 | Page 92

 Which element has two shells, both of which are completely filled with electrons?

Q 3.1 | Page 92

Which element has  the electronic configuration 2, 8, 2?

Q 3.2 | Page 92

Which element has a total of three shells, with four electrons in its valence shell?

Q 3.3 | Page 92

Which element has twice as many electrons in its second shell as in its first shell?

Q 3.5 | Page 92

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

Q 4.1 | Page 92

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

Q 4.2 | Page 92

 An atom has electronic configuration 2, 8, 7.
(a) What is the atomic number of this element?
(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)

Q 5 | Page 92

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 non-metal.
(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?

Q 6 | Page 92

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?

Q 7 | Page 92

How does the electronic configuration of an atom relate to its position in the Modern Periodic Table?

Q 8 | Page 92

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?

Q 9 | Page 92

Compare and contrast the arrangement of elements in Mendeleev’s periodic Table and the Modern Periodic Table.

Q 10 | Page 92

NCERT Science Class 10

Science Textbook for Class 10
S