NCERT solutions Science Textbook for Class 10 chapter 5 Periodic Classification of Elements



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Chapter 5 - Periodic Classification of Elements

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) 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 |

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