SCIENCE AND TECHNOLOGY

1. How many periods and groups are present in the periodic table?

2. Which of the following forms the basis of the modern periodic table?

3. What happens to the electropositive character of elements on moving from left to right in a periodic table?

4. The electronic configuration of an element M is 2, 8, 4. In modern periodic table, the element M is placed in

5. Which of the following is the correct order of the atomic radii of the elements oxygen, fluorine and nitrogen?

6. What is the other name for group 18th elements?

7. Which of the following is the most reactive element of the group 17?

8. 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

9. Which group elements are called transition metals?

10. Which of the following elements has 2 shells and both are completely filled?

11. Which of the following is the atomic number of an element that forms basic oxide?

12. 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?

13. Which of the following does not decrease while moving down the group of the periodic table?

14. An element X belongs to the 3rd period and 1st group of the periodic table. What is the number of valence electrons in its atom?

15. An element M is in group 13th of the periodic table, the formula for its oxide is