CBSE Class 10 Science Entrance Exams Questions and Answers
71 Which of the following does not decrease while moving down the group of the periodic table?
Answer: Valence electrons
72 The elements A, B and C belong to group 2, 14 and 16 respectively, of the periodic table. Which of the two elements will form covalent bonds?
Answer: B and C
76 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
79 Which of the following is the correct order of the atomic radii of the elements oxygen, fluorine and nitrogen?
Answer: F < O < N
80 What happens to the electropositive character of elements on moving from left to right in a periodic table?