Xam Idea Class 12 Chemistry Chapter 7 Solutions: The P-Block Elements

Xam Idea Class 12 Chemistry Solutions Chapter 7 – The p-Block Elements covers all the important aspects of this chapter from inorganic chemistry. These follow the guidelines given by the CBSE Board. Our stepwise and precise solutions to all the exercises help you to grasp the topics thoroughly and score high marks in the Class 12 board exam. They help you develop a strong foundation for higher academic studies and clear all your doubts instantly.

Xam Idea Class 12 Chemistry Solutions Chapter 7 is divided into two major parts. The first part, Part A, contains detailed explanations of all concepts contained in the chapter, along with practice questions. The second part, Part B, contains model test papers, sample question papers and NCERT questions. The best thing about our solutions is that they cover all the types of questions important from the board exam point of view. They also give you ample practice to sharpen your conceptual understanding.

This is an important chapter of inorganic chemistry and deals with general trends in chemical properties in case of groups 15, 16, 17 and 18 falling in the p-block of the periodic table. In this chapter, you learn preparation, properties and uses of several compounds containing these elements. This chapter also tells you about allotropic forms of some elements, the chemistry of interhalogen compounds, uses of noble elements are also discussed in this chapter.

Xam Idea Class 12 Chemistry Chapter 7 – The p-Block Elements

The concepts of Xam Idea Class 12 Chemistry Chapter 7 – The p-Block Elements have been discussed below. 


  • Group 15 Elements


This chapter teaches you that nitrogen (N), phosphorus (P), arsenic (As), antimony (Sb) and bismuth (Bi) are the members of group 15. These occur in the atmosphere, in living beings and earth’s crust in different forms.

Further, the chapter tells you that the general electronic configuration of group 15 elements is ns2np3. While going down in the group, the member elements show a gradation in properties. These elements form compounds with oxygen, hydrogen and halogens on reaction. They exhibit two important oxidation states, + 3 and + 5 but, +3 oxidation is favoured by heavier elements due to ‘inert pair effect’. Our Xam Idea Class 12 Chemistry Solutions Chapter 7 – The p-Block Elements have been drafted by expert and experienced Chemistry teachers systematically, and strategically to help you learn better and score more marks.

Here you also come to know that the element nitrogen behaves differently compared to other elements in the group. This anomaly is due to its small size. It can form pπ–pπ multiple bonds with itself and with highly electronegative atoms, and d orbitals are not available in nitrogen to expand its valence shell.

This section further discusses the preparation and properties of different compounds of nitrogen. The main compounds being N2, NH3, oxides of nitrogen and nitric acid. The oxides of nitrogen have multiple bonds, and some have resonating structures. Further, you come to know about allotropic forms of P, white and red phosphorus, their preparation, and properties along with discussing phosphine, phosphorus halides and oxoacids of phosphorus in detail. Here you will also learn that the oxoacids which have P–H bonds are good reducing agents. Compounds with P-OH bonds show basicity depending upon the number of P–OH groups their basicity varies.


  • Group 16 Elements
    This portion of the chapter tells you all about the elements, oxygen (O), sulphur (S), selenium (Se), tellurium (Te) and polonium (Po). All of these constitute group 16 and have the general electronic configuration ns2np4. These elements can show a maximum of +6 oxidation state, though the other oxidation states shown by them are +2, +4 and +6. As in other groups, gradation in physical and chemical properties is observed.

In this part of the chapter, you learn about the anomalous behaviour shown by oxygen and the reason behind it. Oxygen shows the difference in properties compared to other members of the group because of its high electronegativity value and small size. Also, the absence of d-orbitals limits its covalency to 2 practically and 4 theoretically. Further, you come to know that all the elements react with hydrogen to provide hydrides, with oxygen to form oxides and with halogens to form EX6, EX4 and EX2 in general (where E is a combining element).

Further, you go through the discussion on the individual elements in this chapter. You come to know that O2 is prepared in the laboratory by heating KClO3 in the presence of MnO2. Oxygen forms several oxides with metals. Ozone (O3) is the allotropic form of oxygen, which is highly oxidising in nature. Further, you learn that sulphur forms a number of allotropes, α– and β– forms being the most important ones. Sulphur and oxygen react with each other to give oxides such as SO2 and SO3. Here you will also learn that sulphur dioxide is prepared by the reaction of sulphur with oxygen, and it is used in the manufacture of Sulphuric acid (H2SO4). Sulphur forms a number of oxoacids, H2SO4 being the most important. It is prepared by the contact process and is used as a dehydrating and oxidising agent.


  • Group 17 Elements
    In this part of the chapter, you learn that fluorine (F), chlorine (Cl), bromine (Br) and iodine (I) are the elements constituting group 17 of the periodic table. These elements have ns2np5 as their general electronic configuration. Seawater is a major source of chlorides, bromides and iodides, and fluoride is present mainly as insoluble fluoride minerals. Our Xam Idea Class 12 Chemistry Solutions Chapter 7 – The p-Block Elements are prepared from the examination point of view and cover all significant question styles.


Here, you further come to know that these elements have little tendency to lose electrons, and the common oxidation state of these elements is –1. Some of them still can show the highest oxidation state of +7. You will also learn that these elements are very reactive and are found in nature in a combined state only. The elements of this group show a regular gradation in physical and chemical properties. The common compounds they form are oxides, hydrogen halides, interhalogen compounds and oxoacids.

This part of the chapter further tells you that F shows anomalous properties due to small size, more electronegativity and absence of d orbitals in it. Methods for preparation have been given here and properties of Cl2, HCl have been discussed in detail in this portion. Further, you come to know that halogens combine with one another to form interhalogen compounds of the type XXʹn (n = 1, 3, 5, 7) where Xʹ is lighter than X. Halogens form a number of oxoacids where the halogen is in the centre, bonded in each case with one OH bond as X–OH, in some cases, X = O bonds are also found.


  • Group 18 Elements


This section of the chapter teaches you all about the noble gases of group 18. The elements in this group are helium (He), neon (Ne), Argon (Ar), krypton (Kr), xenon (Xe) and radon (Rn). Their electronic configuration is ns2np6, and all the gases except Rn occur in the atmosphere. As they have complete octet as their outermost configuration, they have minimal tendency to react and form compounds. Here you will also learn that the element xenon is known to have some compounds with fluorine and oxygen formed only under certain conditions. These gases have several uses in our day to day lives. Xam Idea Solutions Chapter 7 – The p-Block Elements are framed in a manner to help you learn all aspects of the chapter effectively and become well acquainted with various question types.

Xam Idea Class 12 Chemistry Chapter 7 – Exercises

This chapter has different types of questions with different marks allotted to them. Some of them are very short answer (VSA) questions, short answer (SA) questions, and long answer questions (LA)questions. These are based on remembering and understanding, higher-order thinking skills (HOTS), application of the concepts based and value application. All of these have been covered in details in our solutions.

This chapter has 51 VSAQs based on general properties of group 15 elements, the chemical reactivity of nitrogen, ozone-depleting aerosols, S compounds. There are 57 SAQs which are based on the reactivity of nitrogen compounds, the reactivity of P and its compounds, S and its compounds, preparation and properties of noble gases, preparation of N2 and NH3. Further, there are explanatory, and reasoning based 23 LAQs which ask about reactions and properties of group 16 compounds, halogens, group 18 elements, Xe compounds especially. Our Xam Idea Class 12 Chemistry Solutions Chapter 2 – Solutions help you in every way to solve these questions.

Apart from these questions given in Part A, there are several important NCERT questions and other questions of previous years’ examinations along with the model question papers, latest CBSE sample papers, previous year’s examination papers given in Part – B of the Xam Idea Class 12 Chemistry Solutions Chapter 7. It is advised to go through all of these papers as well.

Benefits of Xam Idea Class 12 Chemistry Chapter 7 – The p-Block Elements

Some of the major benefits of referring Xam Idea Class 12 Chemistry Solutions Chapter 7 – The p-Block Elements are as follows –

  • They help you build a strong conceptual foundation of the reaction mechanisms and their stereochemical aspects of various compounds.
  • Our solutions give you tips and techniques for solving different types of questions from p-block elements. 
  • They are a handy source of study about all the principles covered in this chapter for effective revision during exams. 
  • They give you a fair idea of the types of questions asked in various exams and ways to solve the same.
  • They have been devised to clear all your doubts instantly.