Nitrogen Family-Group 15 Elements, Periodic Trends, Physical & Chemical Properties, Anomalous Properties of Nitrogen

The contemporary periodic table, devised by Dimitri Mendeleev, lists all known elements according to their atomic number, which is unique to each element. The periodic table was created as a result of such an arrangement. The items with comparable qualities were grouped together in a column.

Nitrogen, phosphorus, arsenic, antimony, and bismuth are all part of Group 15. There is a transition from non-metallic to metallic through metalloidic property as we move down the group. Non-metals are nitrogen and phosphorus, metalloids are arsenic and antimony, while bismuth is a typical metal.

Occurrence of Group 15 Elements

  • Molecular nitrogen makes over 78% of the atmosphere’s volume. It is found in the earth’s crust as sodium nitrate, NaNO3 (also known as Chile saltpeter), and potassium nitrate (Indian saltpeter).
  • Plants and animals both contain it in the form of proteins. Phosphorus is found in the apatite family of minerals, which are the major constituents of phosphate rocks.
  • Phosphorus is a mineral that is found in both animal and plant matter. It can be found in both living and dead cells. Milk and eggs both contain phosphoproteins. Sulphide minerals are the most common form of arsenic, antimony, and bismuth.

As you proceed through the Group 15 elements, starting with the lightest and ending with the heaviest, you’ll see a general flow in attributes as you go down the list. For example, nitrogen is a non-metal gas, but as we progress down the group, we meet metalloids, and finally metal, such as Bismuth. These periodic table patterns aid in the understanding of atom behaviour as well as the prediction of new elements.

The electrical configuration of these elements’ valence shells is ns2 np3. These elements have entirely filled s orbitals and half-filled p orbitals, making their electrical structure extremely stable.

Radii of covalent and ionic (in a certain state) compounds grow in larger as they progress through the group. From N to P, the covalent radius increases dramatically. However, there is only a modest increase in covalent radius from As to Bi. The presence of totally filled d and/or f orbitals in heavier members explains this. 

Due to the progressive rise in atomic size, the ionization enthalpy drops down the group. The ionization enthalpy of group 15 elements is substantially greater than that of group 14 elements in the equivalent periods due to the extra stable half-filled p orbitals electrical configuration and smaller size. As expected, the order of consecutive ionization enthalpies is 

∆H1 < ∆H2 < ∆H

With increasing atomic size, the electronegativity value generally drops down the group. However, the gap is less significant among the heavier elements.

Physical Properties

  • This group’s elements are all polyatomic. All other elements are solids except dinitrogen, which is a diatomic gas.
  • The group’s metallic aspect grows stronger as it progresses. Non-metals are nitrogen and phosphorus, metalloids are arsenic and antimony, and bismuth is a metal. This is owing to an increase in atomic size and a decrease in ionisation enthalpy.
  • In general, boiling points rise from top to bottom in the group, although melting points rise until arsenic and then fall until bismuth.
  • All elements, with the exception of nitrogen, exhibit allotropy.

Chemical Properties

  • Oxidation states and trends in chemical reactivity

These elements’ most common oxidation states are –3, +3, and +5. Because of the increase in size and metallic nature, the tendency to exhibit –3 oxidation state diminishes down the group. Bismuth, the group’s final component, seldom produces any compounds in the –3 oxidation state. The stability of the +5 oxidation state reduces as you progress through the group. BiF5 is the only Bi(V) compound that has been thoroughly studied. The stability of the +5 oxidation state reduces as the group progresses, while the stability of the +3 state improves (owing to the inert pair effect). When nitrogen combines with oxygen, it has oxidation states of + 1, + 2, and + 4. In several oxoacids, phosphorus has oxidation states of +1 and +4.

Since only four orbitals (one s and three p) are available for bonding, nitrogen can only have a maximum covalency of four. The heavier elements contain unoccupied d orbitals in their outermost shells that can be utilised for bonding (covalency) and so enlarge their covalence, as seen in PF6.

  • Anomalous properties of nitrogen

Nitrogen is distinguished from the other members of this group by its small size, high electronegativity, high ionization enthalpy, and lack of d orbital availability. Nitrogen has a unique ability to create p-p multiple bonds with itself and other tiny, electronegativity-rich elements (e.g., C, O). This group’s heavier elements do not form p-p bonds because their atomic orbitals are too vast and diffuse to overlap effectively. Thus, nitrogen is a diatomic molecule having a triple bond between the two atoms (one s and two p). As a result, its bond enthalpy is extremely high. 

Phosphorus, arsenic, and antimony, on the other hand, form single bonds as P–P, As–As, and Sb–Sb, respectively, whereas bismuth forms metallic bonds in its elemental state. However, because of the small bond length, the single N–N bond is weaker than the single P–P bond due to the high interelectronic repulsion of the non-bonding electrons. As a result, the catenation tendency in nitrogen is weaker. Another factor influencing nitrogen chemistry is the lack of d orbitals in its valence shell.

Sample Problems (FAQS)

Question 1: What happens to the size of atoms of elements of p-block as we move from left to right in the same period?

Answer:

In the same time span, the size of the atoms of the elements decreases from left to right. The electrons are added to the same shell because the row is the same. The increase in atomic number, on the other hand, represents the increase in protons, i.e. the positive charge. As a result, the total effective nuclear charge rises. As a result, the electron cloud is dragged even closer to the atom’s nucleus. As a result, the size shrinks.

Question 2: What is covalency?

Answer:

The number of electrons that an atom can share to form chemical bonds is referred to as its covalency. It is usually the number of bonds formed by the atom. 

Question 3: What is the maximum covalency of the nitrogen atom?

Answer:

Nitrogen atoms can share up to four electrons, one in the s-subshell and three in the p-subshell. Furthermore, the lack of d-orbitals limits its covalency to four.

Question 4: Why does nitrogen show a poor tendency towards catenation?

Answer:

The N – N single bond is extremely weak and unstable due to the high magnitude of inter-electronic repulsions of non-bonding electrons, which is caused by the short bond length of the single bond. As a result of the aforementioned factors, the catenation tendency weakens, resulting in instability.

Question 5: What is the primary product of the Haber-Bosch process?

Answer:

Ammonia is the primary byproduct of the Haber-Bosch process.

Er. Neeraj K.Anand is a freelance mentor and writer who specializes in Engineering & Science subjects. Neeraj Anand received a B.Tech degree in Electronics and Communication Engineering from N.I.T Warangal & M.Tech Post Graduation from IETE, New Delhi. He has over 30 years of teaching experience and serves as the Head of Department of ANAND CLASSES. He concentrated all his energy and experiences in academics and subsequently grew up as one of the best mentors in the country for students aspiring for success in competitive examinations. In parallel, he started a Technical Publication "ANAND TECHNICAL PUBLISHERS" in 2002 and Educational Newspaper "NATIONAL EDUCATION NEWS" in 2014 at Jalandhar. Now he is a Director of leading publication "ANAND TECHNICAL PUBLISHERS", "ANAND CLASSES" and "NATIONAL EDUCATION NEWS". He has published more than hundred books in the field of Physics, Mathematics, Computers and Information Technology. Besides this he has written many books to help students prepare for IIT-JEE and AIPMT entrance exams. He is an executive member of the IEEE (Institute of Electrical & Electronics Engineers. USA) and honorary member of many Indian scientific societies such as Institution of Electronics & Telecommunication Engineers, Aeronautical Society of India, Bioinformatics Institute of India, Institution of Engineers. He has got award from American Biographical Institute Board of International Research in the year 2005.

CBSE Class 11 Chemistry Syllabus

CBSE Class 11 Chemistry Syllabus is a vast which needs a clear understanding of the concepts and topics. Knowing CBSE Class 11 Chemistry syllabus helps students to understand the course structure of Chemistry.

Unit-wise CBSE Class 11 Syllabus for Chemistry

Below is a list of detailed information on each unit for Class 11 Students.

UNIT I – Some Basic Concepts of Chemistry

General Introduction: Importance and scope of Chemistry.

Nature of matter, laws of chemical combination, Dalton’s atomic theory: concept of elements,
atoms and molecules.

Atomic and molecular masses, mole concept and molar mass, percentage composition, empirical and molecular formula, chemical reactions, stoichiometry and calculations based on stoichiometry.

UNIT II – Structure of Atom

Discovery of Electron, Proton and Neutron, atomic number, isotopes and isobars. Thomson’s model and its limitations. Rutherford’s model and its limitations, Bohr’s model and its limitations, concept of shells and subshells, dual nature of matter and light, de Broglie’s relationship, Heisenberg uncertainty principle, concept of orbitals, quantum numbers, shapes of s, p and d orbitals, rules for filling electrons in orbitals – Aufbau principle, Pauli’s exclusion principle and Hund’s rule, electronic configuration of atoms, stability of half-filled and completely filled orbitals.

UNIT III – Classification of Elements and Periodicity in Properties

Significance of classification, brief history of the development of periodic table, modern periodic law and the present form of periodic table, periodic trends in properties of elements -atomic radii, ionic radii, inert gas radii, Ionization enthalpy, electron gain enthalpy, electronegativity, valency. Nomenclature of elements with atomic number greater than 100.

UNIT IV – Chemical Bonding and Molecular Structure

Valence electrons, ionic bond, covalent bond, bond parameters, Lewis structure, polar character of covalent bond, covalent character of ionic bond, valence bond theory, resonance, geometry of covalent molecules, VSEPR theory, concept of hybridization, involving s, p and d orbitals and shapes of some simple molecules, molecular orbital theory of homonuclear diatomic molecules(qualitative idea only), Hydrogen bond.

UNIT V – Chemical Thermodynamics

Concepts of System and types of systems, surroundings, work, heat, energy, extensive and intensive properties, state functions. First law of thermodynamics – internal energy and enthalpy, measurement of U and H, Hess’s law of constant heat summation, enthalpy of bond dissociation, combustion, formation, atomization, sublimation, phase transition, ionization, solution and dilution. Second law of Thermodynamics (brief introduction)
Introduction of entropy as a state function, Gibb’s energy change for spontaneous and nonspontaneous processes.
Third law of thermodynamics (brief introduction).

UNIT VI – Equilibrium

Equilibrium in physical and chemical processes, dynamic nature of equilibrium, law of mass action, equilibrium constant, factors affecting equilibrium – Le Chatelier’s principle, ionic equilibrium- ionization of acids and bases, strong and weak electrolytes, degree of ionization,
ionization of poly basic acids, acid strength, concept of pH, hydrolysis of salts (elementary idea), buffer solution, Henderson Equation, solubility product, common ion effect (with illustrative examples).

UNIT VII – Redox Reactions

Concept of oxidation and reduction, redox reactions, oxidation number, balancing redox reactions, in terms of loss and gain of electrons and change in oxidation number, applications of redox reactions.

UNIT VIII – Organic Chemistry: Some basic Principles and Techniques

General introduction, classification and IUPAC nomenclature of organic compounds. Electronic displacements in a covalent bond: inductive effect, electromeric effect, resonance and hyper conjugation. Homolytic and heterolytic fission of a covalent bond: free radicals, carbocations, carbanions, electrophiles and nucleophiles, types of organic reactions.

UNIT IX – Hydrocarbons

Classification of Hydrocarbons
Aliphatic Hydrocarbons:
Alkanes – Nomenclature, isomerism, conformation (ethane only), physical properties, chemical reactions.
Alkenes – Nomenclature, structure of double bond (ethene), geometrical isomerism, physical properties, methods of preparation, chemical reactions: addition of hydrogen, halogen, water, hydrogen halides (Markovnikov’s addition and peroxide effect), ozonolysis, oxidation, mechanism of electrophilic addition.
Alkynes – Nomenclature, structure of triple bond (ethyne), physical properties, methods of preparation, chemical reactions: acidic character of alkynes, addition reaction of – hydrogen, halogens, hydrogen halides and water.

Aromatic Hydrocarbons:

Introduction, IUPAC nomenclature, benzene: resonance, aromaticity, chemical properties: mechanism of electrophilic substitution. Nitration, sulphonation, halogenation, Friedel Craft’s alkylation and acylation, directive influence of functional group in monosubstituted benzene. Carcinogenicity and toxicity.

To know the CBSE Syllabus for all the classes from 1 to 12, visit the Syllabus page of CBSE. Meanwhile, to get the Practical Syllabus of Class 11 Chemistry, read on to find out more about the syllabus and related information in this page.

CBSE Class 11 Chemistry Practical Syllabus with Marking Scheme

In Chemistry subject, practical also plays a vital role in improving their academic scores in the subject. The overall weightage of Chemistry practical mentioned in the CBSE Class 11 Chemistry syllabus is 30 marks. So, students must try their best to score well in practicals along with theory. It will help in increasing their overall academic score.

CBSE Class 11 Chemistry Practical Syllabus

The experiments will be conducted under the supervision of subject teacher. CBSE Chemistry Practicals is for 30 marks. This contribute to the overall practical marks for the subject.

The table below consists of evaluation scheme of practical exams.

Evaluation SchemeMarks
Volumetric Analysis08
Salt Analysis08
Content Based Experiment06
Project Work04
Class record and viva04
Total30

CBSE Syllabus for Class 11 Chemistry Practical

Micro-chemical methods are available for several of the practical experiments. Wherever possible such techniques should be used.

A. Basic Laboratory Techniques
1. Cutting glass tube and glass rod
2. Bending a glass tube
3. Drawing out a glass jet
4. Boring a cork

B. Characterization and Purification of Chemical Substances
1. Determination of melting point of an organic compound.
2. Determination of boiling point of an organic compound.
3. Crystallization of impure sample of any one of the following: Alum, Copper Sulphate, Benzoic Acid.

C. Experiments based on pH

1. Any one of the following experiments:

  • Determination of pH of some solutions obtained from fruit juices, solution of known and varied concentrations of acids, bases and salts using pH paper or universal indicator.
  • Comparing the pH of solutions of strong and weak acids of same concentration.
  • Study the pH change in the titration of a strong base using universal indicator.

2. Study the pH change by common-ion in case of weak acids and weak bases.

D. Chemical Equilibrium
One of the following experiments:

1. Study the shift in equilibrium between ferric ions and thiocyanate ions by increasing/decreasing the concentration of either of the ions.
2. Study the shift in equilibrium between [Co(H2O)6] 2+ and chloride ions by changing the concentration of either of the ions.

E. Quantitative Estimation
i. Using a mechanical balance/electronic balance.
ii. Preparation of standard solution of Oxalic acid.
iii. Determination of strength of a given solution of Sodium hydroxide by titrating it against standard solution of Oxalic acid.
iv. Preparation of standard solution of Sodium carbonate.
v. Determination of strength of a given solution of hydrochloric acid by titrating it against standard Sodium Carbonatesolution.

F. Qualitative Analysis
1) Determination of one anion and one cation in a given salt
Cations‐ Pb2+, Cu2+, As3+, Al3+, Fe3+, Mn2+, Ni2+, Zn2+, Co2+, Ca2+, Sr2+, Ba2+, Mg2+, NH4 +
Anions – (CO3)2‐ , S2‐, NO2 , SO32‐, SO2‐ , NO , Cl , Br, I‐, PO43‐ , C2O2‐ ,CH3COO
(Note: Insoluble salts excluded)

2) Detection of ‐ Nitrogen, Sulphur, Chlorine in organic compounds.

G) PROJECTS
Scientific investigations involving laboratory testing and collecting information from other sources.

A few suggested projects are as follows:

  • Checking the bacterial contamination in drinking water by testing sulphide ion
  • Study of the methods of purification of water.
  • Testing the hardness, presence of Iron, Fluoride, Chloride, etc., depending upon the regional
    variation in drinking water and study of causes of presence of these ions above permissible
    limit (if any).
  • Investigation of the foaming capacity of different washing soaps and the effect of addition of
    Sodium carbonate on it.
  • Study the acidity of different samples of tea leaves.
  • Determination of the rate of evaporation of different liquids Study the effect of acids and
    bases on the tensile strength of fibres.
  • Study of acidity of fruit and vegetable juices.

Note: Any other investigatory project, which involves about 10 periods of work, can be chosen with the approval of the teacher.

Practical Examination for Visually Impaired Students of Class 11

Below is a list of practicals for the visually impaired students.

A. List of apparatus for identification for assessment in practicals (All experiments)
Beaker, tripod stand, wire gauze, glass rod, funnel, filter paper, Bunsen burner, test tube, test tube stand,
dropper, test tube holder, ignition tube, china dish, tongs, standard flask, pipette, burette, conical flask, clamp
stand, dropper, wash bottle
• Odour detection in qualitative analysis
• Procedure/Setup of the apparatus

B. List of Experiments A. Characterization and Purification of Chemical Substances
1. Crystallization of an impure sample of any one of the following: copper sulphate, benzoic acid
B. Experiments based on pH
1. Determination of pH of some solutions obtained from fruit juices, solutions of known and varied
concentrations of acids, bases and salts using pH paper
2. Comparing the pH of solutions of strong and weak acids of same concentration.

C. Chemical Equilibrium
1. Study the shift in equilibrium between ferric ions and thiocyanate ions by increasing/decreasing
the concentration of eitherions.
2. Study the shift in equilibrium between [Co(H2O)6]2+ and chloride ions by changing the
concentration of either of the ions.

D. Quantitative estimation
1. Preparation of standard solution of oxalic acid.
2. Determination of molarity of a given solution of sodium hydroxide by titrating it against standard
solution of oxalic acid.

E. Qualitative Analysis
1. Determination of one anion and one cation in a given salt
2. Cations – NH+4
Anions – (CO3)2-, S2-, (SO3)2-, Cl-, CH3COO-
(Note: insoluble salts excluded)
3. Detection of Nitrogen in the given organic compound.
4. Detection of Halogen in the given organic compound.

Note: The above practicals may be carried out in an experiential manner rather than recording observations.

We hope students must have found this information on CBSE Syllabus useful for their studying Chemistry. Learn Maths & Science in interactive and fun loving ways with ANAND CLASSES (A School Of Competitions) App/Tablet.

Frequently Asked Questions on CBSE Class 11 Chemistry Syllabus

Q1

How many units are in the CBSE Class 11 Chemistry Syllabus?

There are 9 units in the CBSE Class 11 Chemistry Syllabus. Students can access various study materials for the chapters mentioned in this article for free at ANAND CLASSES (A School Of Competitions).

Q2

What is the total marks for practicals examination as per the CBSE Class 11 Chemistry Syllabus?

The total marks for the practicals as per the CBSE Class 11 Chemistry Syllabus is 30. It includes volumetric analysis, content-based experiment, salt analysis, class record, project work and viva.

Q3

Which chapter carries more weightage as per the CBSE Syllabus for Class 11 Chemistry?

The organic chemistry chapter carries more weightage as per the CBSE Syllabus for Class 11 Chemistry.