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
Answer: Mg
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?
Answer: Decreases