CBSE TEST PAPER 01
CLASS XI CHEMISTRY (The p-Block Elements)
General Instruction:
- All questions are compulsory.
- Marks are given along with each question.
1. How many groups are there in p-block? [1]
2. What is inert pair effect? [1]
3. How does metallic and non-metallic character vary in a group? [1]
4. Why do third period elements of p-groups can expand their covalence above four? [1]
5. What type of π–bonds are formed by heavier elements in p-block? [1]
6. Why the elements of group 13 are called p-block elements? [2]
7. The elements B, Al, Ca, In and Tl are placed in the same group of the periodic table. Give reason. [1]
8. In which block of the periodic table, metalloids and non–metals exist? [1]
CBSE TEST PAPER 01
CLASS XI CHEMISTRY (The p-Block Elements)
[ANSWERS]
Ans 1. There are six groups in p-block, numbering from 13 to 18.
Ans 2. The tendency of the ns2 valence electrons of metallic elements to remain unionized or unshared is known as inert pair effect.
Ans 3. The metallic character increases and non-metallic character decreases down the group.
Ans 4. The third period elements of p-groups can expand their covalence above four due to presence of vacant 3d orbitals.
Ans 5. The heavier elements of p-block can form dπ- pπ or dπ- dπ type of π bonds.
Ans 6. Group 13 elements are called p-block elements because the valence shell electronic configuration of the elements is ns2 np1 and the last electron enters the p-orbital.
Ans 7. The elements B, Al, Ga, In and Tl are placed in the same group of the periodic table because they have same valence shell electronic configuration ns2 np1.
Ans 8. The non-metals and metalloids exist only in the p-block of the periodic table.