S-block elements are those elements in which the last electron is present in the s-orbital. In the periodic table. They reside in the first 2 columns. S-block consists of 14 elements that include, Hydrogen (H), Lithium (Li), Helium (He), Sodium (Na), Beryllium (Be), Potassium (K), Magnesium (Mg), Rubidium (Rb), Calcium (Ca), Caesium (Cs), Strontium (Sr), Francium (Fr), Barium (Ba), and Radium (Ra).
Table of Contents
What are s-block Elements?
You all are well-familiar with the concept of the modern periodic table. In the modern periodic table, we learn about 4 kinds of blocks i.e. s-block, p-block, d-block & f-block. Here, we will learn the definition of s-block elements. It is the most intriguing block of the periodic table.
The element which enters in the outermost s-orbital are known as s-block elements.
S-block elements consists 2 groups i.e. Group 1 & Group 2. Group 1 consists elements which are called as alkali metals while Group 2 consists metals which are called as alkaline earth metals.
Group 1- Alkali Metals
Group 2- Alkaline Earth Metals
What are Alkali Metals of Group 1?
Have you ever wondered why sodium causes a fizzy explosion when it is dropped in water? We will uncover this further.
Group 1 elements are called alkali metals because they make hydroxides, whenever reacts with water. You all know that water is strongly alkaline. Here you got your answer for the above question.
Alkali metals are well-known for their extreme reactions & their easy bond with other elements. The elements of Group 1 have 1 valence electron in their outermost s-orbital.
What are Alkaline Earth Metals of Group 2?
During any occasion, you buy fireworks right? And when you light them up, they starts glowing & gives a beautiful view. It’s the magic of none other than our magnesium.
Group 2 introduces us the alkaline earth metals which exists in the earth’s crust. The interesting thing here is that their oxides & hydroxides are alkaline in nature. The elements of Group 2 have 2 valence electrons in their outermost s-orbital.
Table of S-block Elements & Their Symbol
S-block comprises total 14 elements which are classifies into 2 groups: Group 1 & Group 2. The classification of these 14 elements are given below in tabular form:
S-block elements
Group 1 (Alkali Metals)
Group 2 (Alkaline Earth Metals)
Name of Elements
Symbol
Name of Elements
Symbol
Hydrogen
H
Beryllium
Be
Lithium
Li
Magnesium
Mg
Sodium
Na
Calcium
Ca
Potassium
K
Strontium
Sr
Rubidium
Rb
Barium
Ba
Cesium
Cs
Radium
Ra
Francium
Fr
Helium
He
Electronic Configuration of S-block elements
Electronic Configuration of s-block elements is added in the image below,
S-block Elements
Group 1 (Alkali Metals)
Group 2 (Alkaline Earth Metals)
Name of elements
Electronic Configuration
Name of elements
Electronic Configuration
Hydrogen
1s1
Beryllium
[He]2s2
Lithium
[He]2s1
Magnesium
[Ne]3s2
Sodium
[Ne]3s1
Calcium
[Ar]4s2
Potassium
[Ar]4s1
Strontium
[Kr]5s2
Rubidium
[Kr]5s1
Barium
[Xe]6s2
Cesium
[Xe]6s1
Radium
[Rn]7s2
Francium
[Rn]7s1
Helium
1s2
Difference between Group 1A and Group 2A Elements
Let’s learn the basic differences between the elements of Group 1 & Group 2 on the basis of some characteristics:
Characteristics
Group 1 (Alkali Metals)
Group 2 (Alkaline Earth Metals)
Reactivity
These are highly reactive elements.
These are less reactive elements.
Oxidation State
These have oxidation state as +1
These have oxidation state as +2
Electrons in outermost shell
These have only 1 electron.
These have 2 electrons.
Melting & Boiling Point
These have low melting & boiling point.
These have high melting & boiling point.
Properties of s-block Elements
The S-block elements possesses distinct properties. In this section, you’ll learn about the properties of s-block elements. Their properties mainly categorized into 2 parts:
Physical Properties
Chemical Properties
Physical Properties of s-block Elements
Let’s dive deep into the properties of s-block elements
Melting Point: S-block elements consists different melting points. The Group 1 elements i.e. Alkali metals have low melting point. For example, Sodium can be melted around 98° celsius. When we talk about Group 2 elements i.e. Alkaline Earth Metals, they have high melting point. For example, Calcium needs 842° celsius temperature to melt which is 9 times more than sodium needs.
Conductivity: Due to the presence of electrons that are loosely bound, these electrons can easily move through the metallic structure. This encourages the flow of electricity. That’s why s-block elements have higher electrical conductivity.
Nature of Bonds: In S-block, the Group 1 elements i.e. Alkali metals always form ionic bonds as these elements have low ionization enthalpies that decreases downwards to the group. In simple words, as we move down the group, the ionic characteristic increases.
Density: The densities of s-block elements is relatively low due to their large size.
Photoelectric effect: The s-block elements shows photoelectric effect. They emit electrons from their surface, when they come into the contact of light. Lithium is an exception here because of its higher ionization enthalpy.
Chemical Properties of s-block Elements
Now, it’s time to learn about the chemical properties of S-block elements:
Reactivity: S-block elements are highly reactive in nature. Group 1 elements especially Na and K are well-known for their high reactivity with water that results in producing hydrogen gas & hydroxides. Group 2 metals are less reactive as compared to Group 1 elements but still they show a notable reactivity when exposed to air or water.
Formation of Compounds: S-block elements have high tendency to make compounds. They donate their electrons to form ionic compounds. Group 1 elements donate 1 valence electron while Group 2 elements donate 2 valence electrons to form a compound.
Reducing Agents: Due to the strong tendency of loosing electrons, s-block elements are known as strong reducing agents.
Atomic Mass of s-block Elements
Atomic mass is the total mass of the protons & neutrons in an atom of the element. It is denoted by atomic mass per unit i.e. a.m.u or g/mol.
Atomic mass of S-block elements refers to the average mass of the atoms of a particular element, taking into account the various isotopes and their relative abundances in nature.
Atomic masses of the s-block elements changes as we go down the groups. The number of protons & neutrons increases and that’s why the atomic mass also increases.
s-block Elements & Their Atomic Masses
The table added below shows the s-block elements and their atomic mass
S-Block Elements
Group 1 (Alkali Metals)
Group 2 (Alkaline Earth Metals)
Name of Element
Atomic Mass
Name of Element
Atomic Mass
Hydrogen
1.008 amu
Beryllium
9.012 amu
Lithium
22.99 amu
Magnesium
24.305 amu
Sodium
22.98 amu
Calcium
40.08 amu
Potassium
39.10 amu
Strontium
87.62 amu
Rubidium
85.47 amu
Barium
137.33 amu
Cesium
132.91 amu
Radium
226 amu
Francium
223 amu
Helium
4.0026 amu
Diagonal Relationship of s-Block Elements
Diagonal relationship is the relationship which shows a similar behavior between certain elements. These elements are located diagonally across each other within the same group but different periods of a periodic table.
For example. Lithium (Li) and Magnesium (Mg) have a diagonal relationship. Due to their similar ionic sizes and electronic configurations, they show similarities. Even after being in different periods, they have a very similar size of ions which forms a diagonal relationship between them.
Some of the similarities observed in these diagonal relationships include:
Similar Ionic radii– Certain elements have remarkably similar ionic sizes. For example, Lithium (Li) and Magnesium (Mg} & Beryllium (Be) and Aluminum (Al).
Common chemical behavior– Diagonal elements show similarity in their chemical reactions. For example, Lithium (Li) and Magnesium (Mg} & Beryllium (Be) and Aluminum (Al).
Complex formation– Due to their anonymous charge densities and electronic configurations, diagonal elements form similar kind of complexes. For example, Lithium (Li) and Magnesium (Mg}.
Oxidation state– Diagonal elements tend to show similar oxidation state in some cases. For example,Beryllium (Be) and Aluminum (Al).
Periodic Trends in s-Block Elements
S-block elements show several kind of periodic trends. As you move down to the group:
Atomic size of the elements increases due to the addition of electron shells.
Metallic character of the s-block elements follows a certain pattern from left to right. The elements on left like Alkali metals easily lose electrons and shows strong metallic properties. While the elements on right like halogens and noble gases have more non-metallic traits. This happens due to the decreasing atomic sizes.
As you move down the group, the reactivity of s-block elements increases due to the increase in their atomic sizes.
Due to the increasing atomic size & shielding effect, the s-block elements need less energy to remove electrons which results in the decline of ionization energy.
Compounds of s-block Elements
Here are preparations & properties of some important compounds of S-block elements:
Sodium Hydroxide (NaOH)
Preparation: Sodium hydroxide is generally prepared through the electrolysis of aqueous sodium chloride or via the reaction of sodium carbonate with calcium hydroxide.
Properties: It is a white solid with high solubility in water and form a strongly alkaline solution. It is a strong base which is used in various industries such paper production, detergents, and in the chemical industry.
Calcium Carbonate (CaCO3)
Preparation: Calcium carbonate is naturally occured and can be obtained from limestone, chalk, or marble. It’s also prepared through precipitation reaction by mixing calcium chloride & sodium carbonate.
Properties: It is a white, odorless powder with a variety of applications such as cement production, diet supplement, plastic manufacturing and as a filler in paints and coatings.
Sample Questions on s-Block Elements
Q1: Determine the atomic mass of following elements:
Solution:
Atomic mass of the given elements is,
Na= 6.94 a.m.u.
Ra= 226 a.m.u.
Q2: Which of the following is alkaline earth metal?
Sodium
Potassium
Radium
Francium
Solution:
Option is (3) Radium is Correct. Radium is an alkaline earth metal.
Q3: Write the electronic configuration of following s-block elements:
Solution:
Electronic configuration of following s-block elements is:
Calcium= [Ar]4s2
Francium= [Rn]7s1
Helium= 1s2
FAQs on s-Block Elements
What are s-Block Elements?
The elements which occupies the outermost shell are known as s-block elements.
How to Differentiate between Group 1 and Group 2 Elements?
Group 1 elements have only 1 valence electrons in their outermost orbital while Group 2 elements have 2 valence electrons.
Are All s-Block Elements Metals?
Mostly s-block elements are metals due to their strong metallic properties. Here, hydrogen is an exception as it displays non-metallic characteristic and behave more like a gas.
Where Can we Find s-Block Elements in Periodic Table?
s-block elements are found in a left most columns of a periodic table.
What is the General Electronic Configuration of s-block Elements?
The general electronic configuration of s-block element is ns2np(1-6)
Which group consists of s-block Elements?
Group 1 and Group 2 of periodic table contains s-block elements.
Neeraj Anand, Param Anand
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 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 Scheme
Marks
Volumetric Analysis
08
Salt Analysis
08
Content Based Experiment
06
Project Work
04
Class record and viva
04
Total
30
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 theapproval 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.
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