NCERT Solutions for Class 9 Science Chapter 3 - Atoms and Molecules
Chapter 3 of Class 9 Science, "Atoms and Molecules," is an essential topic that helps students understand the basic building blocks of matter. This chapter covers the basics of atoms, and molecules, and the laws that govern their behaviour, like the law of conservation of mass.
This article will provide students with high-quality NCERT solutions for class 9 science chapter 3, Atoms and Molecules. These exercises are devised specifically to help students practice problems, recall important concepts, and enhance their critical and problem-solving skills. Class 9 NCERT Solutions for Atoms and Molecules are developed by ALLEN's subject experts and include the entire chapter concepts as per the latest CBSE curriculum.
1.0Science Class 9 Science Chapter 3 NCERT Solutions - Download PDF
NCERT Solutions Class 9 Science Chapter 3: Atoms and Molecules
2.0Topics and Sub-Topics in Class 9 Science Chapter 3 Atoms and Molecules
Atoms and Molecules
Laws of Chemical Combination
What is an Atom?
What is a Molecule?
Writing Chemical Formulae
Molecular Mass and Mole Concept
3.0NCERT Questions with Solutions for Class 9 Science Chapter 3 - Detailed Solutions
In a reaction, 5.3 g of sodium carbonate reacted with 6 g of ethanoic acid. The products were 2.2 g of carbon dioxide, 0.9 g water and 8.2 g of sodium ethanoate. Show that these observations are in agreement with the law of conservation of mass.
Ans. Sodium carbonate reacts with ethanoic acid converted into sodium ethanoate, carbon dioxide, and water.
(5.3+6)g=11.3g⟶(8.2+2.2+0.9)g=11.3g∴ Total mass before the reaction
= Total mass after the reaction
Hence, the given observations are in agreement with the law of conservation of mass.
Hydrogen and oxygen combine in the ratio of 1:8 by mass to form water. What mass of oxygen gas would be required to react completely with 3 g of hydrogen gas?
Ans. It is given that the ratio of hydrogen and oxygen by mass to form water is 1:8.
Then, the mass of oxygen gas required to react completely with 1 g of hydrogen gas is 8 g .
Therefore, the mass of oxygen gas required to react completely with 3 g of hydrogen gas is 8×3g=24g.
Which postulate of Dalton's atomic theory is the result of the law of conservation of mass?
Ans. The postulate of Dalton's atomic theory is, atoms are indivisible particles, which can neither be created nor destroyed in a chemical reaction.
Which postulate of Dalton's atomic theory can explain the law of definite proportions?
Ans. The postulate of Dalton's atomic theory based on the law of definite proportion is:
"The relative number and kind of atoms in a given compound remains constant."
Define atomic mass unit.
Ans. Atomic mass unit equal to exactly onetwelve the mass of one atom of carbon12 is called one atomic mass unit. It is written as ' u '.
Why is it not possible to see an atom with naked eyes?
Ans. The size of an atom is too small that's why it is not possible to see it with naked eyes.
Write down the formulae of
(i) sodium oxide
(ii) aluminium chloride
(iii) sodium sulphide
(iv) magnesium hydroxide
Ans. (i) Sodium oxide : Na2O
(ii) Aluminium chloride : AlCl3
(iii) Sodium suphide : Na2S
(iv) Magnesium hydroxide : Mg(OH)2
Write down the names of compounds represented by the following formulae:
(i)Al2(SO4)3
(ii) CaCl2
(iii) K2SO4
(iv) KNO3
(v) CaCO3
Ans. (i) Al2(SO4)3 : Aluminium sulphate
(ii) CaCl2 : Calcium chloride
(iii) K2SO4 : Potassium sulphate
(iv) KNO3 : Potassium nitrate
(v) CaCO3 : Calcium carbonate
What is meant by the term chemical formula?
Ans. The chemical formula of a compound means the symbolic representation of the composition of a compound. For example, from the chemical formula CO2 of carbon dioxide, we come to know that one carbon atom and two oxygen atoms are chemically bonded together to form one molecule of the compound, carbon dioxide.
How many atoms are present in a
(i) H2S molecule and
(ii) PO43− ion?
Ans. (i) In a H2S molecule, three atoms are present: two of hydrogen and one of sulphur.
(ii) In a PO43− ion, five atoms are present: one of phosphorus and four of oxygen.
Calculate the molecular masses of H2,O2, Cl2,CO2,CH4,C2H6,C2H4,NH3,CH3OH.
Ans. Molecular mass of H2=2× Atomic mass (H)=2×1=2u
Molecular mass of O2=2× Atomic mass (0)=2×16=32u
Molecular mass of Cl2=2× Atomic mass (Cl)=2×35.5=71u
Molecular mass of CO2= Atomic mass (C) +2× Atomic mass ( 0 )
=12+2×16=44u
Molecular mass of CH4= Atomic mass (C) +4× Atomic mass ( H )
=12+4×1=16u
Molecular mass of C2H6=2× Atomic mass of C+6× Atomic mass
of H=2×12+6×1=30u
Molecular mass of C2H4=2× Atomic mass (C) +4× Atomic mass
(H) =2×12+4×1=28u
Molecular mass of NH3= Atomic mass of N+3× Atomic mass of
H=14+3×1=17u
Molecular mass of CH3OH= Atomic mass (C) +4× Atomic mass (H) + Atomic mass (0)
=12+4×1+16=32u
Calculate the formula unit masses of ZnO,Na2O,K2CO3, given atomic masses of Zn=65u,Na=23u,K=39u,C=12 u , and 0=16u.
Ans. Formula unit mass is defined as the sum of the atomic masses of all atoms that are present in a formula unit of the given compound.
Atomic mass of Zn=65u
Atomic mass of Na=23u
Atomic mass of K=39u
Atomic mass of C=12u
Atomic mass of 0=16u
Calculating the formula unit masses of the given compounds:
ZnO=Zn+OZnO=(65+16)u=81uNa2O=2Na+0Na2O=[(2×23)+16]uNa2O=(46+16)u=62uK2CO3=2K+C+30K2CO3=[(2×39)+12+(3×16)]K2CO3=(78+12+48)u=138u
A 0.24 g sample of compound of oxygen and boron was found by analysis to contain 0.096 g of boron and 0.144 g of oxygen. Calculate the percentage composition of the compound by weight.
Ans. Mass of boron =0.096g (Given)
Mass of oxygen =0.144g (Given)
Mass of sample =0.24g (Given)
Percentage of boron
= Mass of sample Mass of boron ×100=0.240.096×100=40%
Percentage of O2= Mass of sample Mass of oxygen ×100=0.240.144×100=60%
Thus, percentage of boron by weight in the compound =40%
And, percentage of oxygen by weight in the compound =60%
When 3.0 g of carbon is burnt in 8.00 g oxygen, 11.00 g of carbon dioxide is produced. What mass of carbon dioxide will be formed when 3.00 g of carbon is burnt in 50.00 g of oxygen? Which law of chemical combinations will govern your answer?
Ans. Carbon + Oxygen → Carbon dioxide 3 g of carbon reacts with 8 g of oxygen to produce 11 g of carbon dioxide.
If 3 g of carbon is burnt in 50 g of oxygen, then 3 g of carbon will react with 8 g of oxygen. The remaining 42 g of oxygen will be left unreactive.
In this case also, only 11 g of carbon dioxide will be formed.
The above answer is governed by the law of constant proportions.
What are polyatomic ions? Give examples?
Ans. A polyatomic ion is a group of atoms carrying a charge (positive or negative). For example, ammonium ion, hydroxide ion (OH−), carbonate ion(CO32−), sulphate ion (SO42−).
Write the chemical formulae of the following:
(a) Magnesium chloride
(b) Calcium oxide
(c) Copper nitrate
(d) Aluminium chloride
(e) Calcium carbonate
Ans. (a) Magnesium chloride: MgCl2
(b) Calcium oxide: CaO
(c) Copper nitrate : Cu(NO3)2
(d) Aluminium chloride : AlCl3
(e) Calcium carbonate: CaCO3
Give the names of the elements present in the following compounds:
(a) Quick lime
(b) Hydrogen bromide
(c) Baking powder
(d) Potassium sulphate
Compound
Chemical formula
Elements present
Quick lime
CaO
Calcium, oxygen
Hydrogen bromide
HBr
Hydrogen, bromine
Baking powder
NaHCO3
Sodium, hydrogen, carbon, oxygen
Potassium sulphate
K2SO4
Potassium, sulphur, oxygen
Exercise-01
Multiple choice questions
Hydrogen reacts with oxygen to form water (H2O). The ratio between masses of hydrogen and oxygen is
(1) 1:8
(2) 6.5:8
(3) 2:1
(4) 6.5:16
In carbon dioxide, carbon and oxygen are present in the ratio of .
(1) 3:8
(2) 2:12
(3) 2:3
(4) 1:2
The quantity of matter present in an object is called its .
(1) mass
(2) volume
(3) density
(4) vapour pressure
Which of the following is not correct according to Dalton's atomic theory?
(1) Matter is made up of atoms.
(2) Atoms of all substances are identical in all respects.
(3) Atoms combine in a simple whole number ratio.
(4) Atoms of two elements can combine to form more than one compound.
Indivisibility of an atom was proposed by
.
(1) Dalton
(2) Rutherford
(3) Thomson
(4) Bohr
Which of the following does not change when a chemical reaction takes place?
(1) Volume
(2) Mass
(3) Physical properties
(4) Chemical properties
All samples of carbon dioxide contain carbon and oxygen in the mass ratio of 3:8. This is in agreement with the Law of
_.
(1) conservation of Mass
(2) constant Proportion
(3) multiple Proportion
(4) reciprocal Proportion
Which of the following statements is not true about an atom?
(1) Atoms are not able to exist independently.
(2) Atoms are the basic units from which molecules and ions are formed.
(3) Atoms are always neutral in nature.
(4) Atoms aggregate in large numbers to form the matter that we can see, feel or touch.
The first scientist to use the symbols of elements was
(1) Dalton
(2) Berzelius
(3) Kanad
(4) Proust
The chemical symbol for barium is
(1) B
(2) Ba
(3) Be
(4) Bi
The chemical symbol P stands for
(1) phosphorus
(2) potassium
(3) polonium
(4) promethium
Kalium is the Latin name of _.
(1) potassium
(2) krypton
(3) calcium
(4) phosphorus
The chemical symbol for sodium is
(1) So
(2) Sd
(3) NA
(4) Na
The chemical symbol for nitrogen gas is
(1) Ni
(2) N2
(3) N+
(4) N
The atomicity of K2Cr2O7 is
(1) 9
(2) 11
(3) 10
(4) 12
A group of atoms chemically bonded together is a/an
(1) molecule
(2) ion
(3) salt
(4) element
An atom is 15 times heavier than 121 th of the mass of carbon atom (C-12 isotope). The mass in a.m.u is .
(1) 1.25
(2) 15
(3) 14
(4) 12
The number of atoms in a molecule of the elementary substance is called .
(1) atomic number
(2) avogadro number
(3) atomic mass
(4) atomicity
The unit of atomic mass is
(1) gm
(2) u
(3) litre
(4) mp
A substance in which all atoms are alike is called a/an
(1) molecule
(2) ion
(3) homogeneous
(4) element
An example of a triatomic molecule is
.
(1) ozone
(2) nitrogen
(3) carbon monoxide
(4) hydrogen
The smallest particle of a substance that is capable of independent existence is
.
(1) atom
(2) molecule
(3) electron
(4) proton
One atomic mass unit is equal to weight of
(1) one atom of hydrogen
(2) 1/16 th of oxygen atom
(3) 1/12 th of natural carbon atom
(4) 1/12 th of C−12 isotope of carbon.
The formula of sulphuric acid is
(1) H2SO3
(2) H2SO4
(3) H2SO5
(4) H2S2O7
The chemical formula of the copper (II) nitrate
(1) Cu(NO3)2
(2) CuNO3
(3) Cu2(NO3)3
(4) Cu2NO3
The correct formula of aluminium sulphate is
(1) AlSO4
(2) Al2SO4
(3) Al3(SO4)2
(4) Al2(SO4)3
Formula of Calcium phosphate is
(1) CaPO4
(2) Ca2(PO4)3
(3) Ca(PO4)2
(4) Ca3(PO4)2
Which of the following elements are mono-atomic?
(1) Iron
(2) Sodium
(3) Helium
(4) Chlorine
Formula unit mass is used for the mass of the following compound
(1) CaO
(2) H2S
(3) CCl4
(4) CH4
Which one of the following does not represent correct molecular formula of a compound?
(1) 2CH3
(2) CH4
(3) CH3OH
(4) (CH3)2
Formula mass is not used in case of
(1) NaCl
(2) MgCl2
(3) CCl4
(4) CaO
Formula mass but not molecular mass is used for substance whose constituent particles are
(1) ions
(2) similar
(3) uniform
(4) none of these
The overall charge on an ionic compound is equal to
(1) charge of the cation present
(2) zero
(3) charge of the anion present
(4) sum of charges of the cation and anion
1u or 1amu means
(1) 12th 1 mass of C−12 atoms
(2) mass of C−12 atoms
(3) mass of 0-16 atoms
(4) mass of hydrogen molecule
True or False
Democritus called the indivisible particles of matter as 'atoms'.
Proust gave the law of conservation of mass.
A molecule is unstable while an atom is quite stable.
Dalton's symbol for ZnSO4 is.
Atomic mass when expressed in grams is known as gram atomic mass.
Molecules of an element are homoatomic
while that of a compound are heteroatomic.
Latin name of tin is stannum.
Symbol of mercury is Me .
C17H35COONa has the atomicity of 52 .
The molecular formula of potassium nitrate is KNO3.
Fill in the blanks
During a chemical reaction, the sum of the ____ of the reactants and products remains unchanged.
In a pure chemical compound, elements are always present in a proportion by mass.
Latin name of mercury is .
The abbreviation used for lengthy names of elements are termed as their _.
In ionic compounds, the charge on each ion is used to determine the of the compound.
The number of atoms in a molecule of the elementary substance is called its
.
Those ions which are formed from single atoms are called .
Clusters of atoms that act as an ion are called ions.
A chemical formula is also known as
.
In 816O, the number 16 stands for
.
Match the column
Match the following elements and compounds given in column-A with the value of their atomicity given in column-B
Column-A
Elements/compound
Column-B
Atomicity
1
Argon
a
8
2
Sulphur
b
4
3
Oxygen
c
2
4
Phosphorous
d
1
5
Ozone
e
3
6
Bromine
f
5
7
Carbon monoxide
g
6
8
Hydrogen peroxide
h
7
9
Lime water
10
Ammonia
11
Quick Lime
12
Baking Powder
13
Limestone
14
Common salt
15
Sodium Sulphate
Crossword puzzle
In this crossword puzzle, name of 11 elements are hidden. Symbols of these are given below. Complete the puzzle.
(1) Cl
(2) H
(3) Ar
(4) 0
(5) Xe
(6) N
(7) He
(8) F
(9) Kr
(10). Rn
(11) Ne
What is the ratio between masses of
(i) hydrogen and oxygen in H2O
(ii) nitrogen and hydrogen in NH3 ? [Atomic mass of H=1u,O=16u, N=14u ]
10 g silver nitrate solution is added to 10 g of sodium chloride solution. What change in mass do you expect after the reaction?
Name the building block of all matter.
What are the symbols of copper and cobalt?
Give symbols for the following elements: Aluminium, Tin, Bromine, Neon.
Why is copper represented by the symbol 'Cu' while there is no letter ' u ' in the name?
What do you understand by the 'atomicity' of the substance?
Give two examples each of bivalent cations and bivalent anions.
What is 1 u ?
What is meant by formula unit mass? Short answer type questions
What is the first law of chemical combination?
What is the conclusion of the Dalton's atomic theory?
Define the "law of constant proportions". How does Dalton's atomic theory explain the truth of the law?
What are poly atomic ions? Give example.
What is the difference between the actual mass of a molecule and gram molecular mass?
What is meant by the term chemical formula?
Give the names of the elements present in the following compounds.
(i) Sodium bicarbonate
(ii) Calcium carbonate
(iii) Hydrogen bromide
Write the molecular formula of the following and give the ratio by mass of atoms present in
(i) Ammonia
(ii) Water
(iii) Methane
Write down the names of the compound represented by the following formula
(i) Al2(SO4)3
(ii) CaCl2
(iii) K2SO4
(iv) KNO3
What is the necessity of mole concept?
Long answer type questions
What are the postulates and limitations of Dalton's atomic theory?
State and explain the following:
(i) Atom
(ii) Molecule
(iii) Atomic mass
(iv) Molecular mass
Write the formulae for the following and calculate the molecular mass for each one of them.
(a) Potassium hydroxide
(b) Sodium bicarbonate
(c) Calcium carbonate
(d) Magnesium chloride
(e) Sodium chloride
Write the formula and names of compounds formed by
(a) Na+and HCO3−
(b) K+and CO32−
(c) Cu2+ and SO42−
(d) Cu2+ and O2−
(e) Na+and SO42−
(f) NH4+and CO32−
Valencies or the charge numbers of some ions are given below:
Aluminium ion 3+
Magnesium ion 2+
Potassium ion 1+
Nitride ion 3-
Sulphate ion 2−
Fluoride ion 1−
Using the above information, write down the chemical formulae of the following:
(i) Aluminium fluoride
(ii) Magnesium nitride
(iii) Aluminium sulphate
(iv) Potassium fluoride
(v) Magnesium fluoride
(vi) Potassium nitride
Exercise-01 Solutions
Multiple choice questions
Option (1)
H:O⇒2×1:16⇒1:8
Option (1)
C: 0⇒12:16×2⇒3:8
Option (1)
The quantity of matter present in an object is called its mass.
Option (2)
Atoms of all substances are identical in all respects.
Above statement is not in accordance with Daltons Atomic theory.
Option (1)
Dalton : Indivisibility of atom was proposed by Dalton.
Option (2)
Mass : According to law of conservation of mass "mass can neither be created nor be destroyed".
Option (2)
Law of constant proportions: "In a given substance, all the constituent elements remain present in a definite proportion by mass irrespective of their sources".
Option (1)
Atoms may (e.g., He, Ne, Ar, etc) or may not exist independentely.
Option (1)
John Dalton was the first scientist to use symbol for element.
Option (2)
The chemical symbol for barium is 56137 Ba.
Option (1)
Phosphorus is a chemical element and with symbol P and atomic number 15.
Option (1)
Some symbols have been taken from the names of elements in Latin, German or Greek.
Ex. Symbol of potassium is K from its Latin name is "Kalium".
Option (4)
The chemical symbol of sodium is 1123Na
It is derived from Latin name "Natrium".
Option (2)
Nitrogen gas is a diatomic molecule composed of two nitrogen atoms. Therefore it exists as N 2 .
Option (2)
(K=2)+(Cr=2)+(O=7)=11
Option (1)
A group of atoms chemically bonded together is a molecule.
Option (2)
15
Mass in amu is the number of times an atom or molecule heavier than 1/12th of the mass of 612C atom.
Option (4)
The number of atoms present in 1 molecule of elementary substance is called its atomicity.
Ex. In H2O molecule 2 Hydrogen atoms and 1 Oxygen atom are present hence atomicity of H2O is 3 .
Option (2)
The unit of atomic mass "U" (Unified mass) or amu.
Option (4)
Simplest chemical substance where all the atoms are exactly same.
Option (1)
In ozone molecule 3 atoms are present Ozone ( O3 ); Nitrogen ( N2 ) contains two atoms; Carbonmonoxide (CO) contain two atoms; Hydrogen (H2) contain two atoms.
Option (2)
The smallest particle of substance that is capable of independent existence is molecule.
Option (4)
One atomic mass unit is equal to 1.66×10−24g. it is equal to 1/12th of the mass of an atom of carbon -12 , it is abbreviated as amu.
Option (2)
The formula of sulphuric acid is H2SO4.
Option (1)
Cu(NO3)2
Option (4)
Al2(SO4)3
Option (4)
Ca3(PO4)2
Option (4)
Copper nitrate Cu(NO3)2Cu2++2NO3−→Cu(NO3)2
Option (3)
All the inert gases are monoatomic.
Option (1)
Formula unit mass is used for ionic compounds. Among the options only CaO is the ionic compound rest all are molecular covalent compounds.
Option (1)
2CH3
Option one represents two methyl radicals whereas other three options represents methane, methanol and ethane, respectively.
Option (3)
Formula unit mass is always used for ionic compounds, among the options only CCl4 is covalent compound.
Option (1)
Formula unit mass is always used for ionic compounds.
Option (2)
During the representation of formula unit, ions are arranged in such a number that total charge on the Ionic compound is equal to zero.
Option (1)
1 u or 1 amu means 12th 1
mass of C-12 atoms
Sum of the masses of ingredient ions present in the molecular formula of given compound.
Short answer type questions
Law of conservation of masses "During any chemical process, mass neither be created nor be destroyed."
Dalton's atomic theory :-
(1) Every matter is made up of very small particles known as atoms.
(2) Atoms are the ultimate particles of matter which cannot be created or destroyed in a chemical reaction and cannot be further subdivided into smaller particles.
(3) All atoms of a particular element are identical in all respects. This means that they have same mass, size and also same chemical properties
(4) Atoms of different elements have different masses, sizes and also chemical properties.
(5) Atoms are the smallest particles of matter which can take part in chemical combination.
(6) Atoms of the same or different elements combine in small whole number ratios to form molecules of a element/compound.
(7) The relative number and kinds of atoms are constant in a given compound.
(8) Atoms of two different elements may combine in different ratios to form more than one compound. For example, carbon and oxygen may combine to form carbon monoxide (CO) and carbon dioxide ( CO2 ) in which the ratios of the combining atoms (C and 0) are 1:1 and 1:2 respectively.
Explanation of law of constant proportion: According to one of the postulates of Dalton's atomic theory, the number and kind of atoms in a compound is fixed.
This implies that a compound is always made up of the same elements and the ratio of the atoms in the compounds is fixed. As atoms have fixed masses, this means that in the compound, the elements are combined in a fixed ratio by mass.
Polyatomic Ions : Ions which are constituted by ≥3 atoms. e.g. NH4+; HSO4−; PO43− etc.
Actual mass : Exact mass of a molecule Gram molecular mass. Sum of the masses of 6.023×1023 molecules.
Chemical formula : A set of atomic symbols which shows type and number of constituent elements.
It relates number of atoms/particles /molecules/mass of the substance.
Long answer type questions
Dalton Atomic Theory:
Postulates of Dalton's atomic theory
The important features of the Dalton's Atomic theory are listed,
1.Every matter is made up of very small particles known as atoms.
2.Atoms are the ultimate particles of matter which cannot be created or destroyed in a chemical reaction and cannot be further subdivided into smaller particles.
3.All atoms of a particular element are identical in all respects. This means that they have same mass, size and also same chemical properties.
4.Atoms of different elements have different masses, sizes and also chemical properties.
5.Atoms are the smallest particles of matter which can take part in chemical combination.
6 Atoms of the same or different elements combine in small whole number ratios to form molecules of a element/compound.
7.The relative number and kinds of atoms are constant in a given compound.
8.Atoms of two different elements may combine in different ratios to form more than one compound. For example, carbon and oxygen may combine to form carbon monoxide (CO) and carbon dioxide (CO2) in which the ratios of the combining atoms ( C and 0 ) are 1:1 and 1:2 respectively.
Drawbacks:
(i) Atom is no more indivisible, instead of fact it is composed of −1e,+1p,0n.
(ii) Atoms of same element may have different masses i.e., isotopes.
(iii) Different atoms may have same masses, i.e., isobars.
(iv) Substances having same element may have different physical properties i.e., Allotropes.
(v) Atoms may combine in fixed and integral ratio but not simple always.
1.Atom: Basic unit and smallest part of any matter is made up of electron, protons and neutrons.
2.Molecule: A group of atoms bonded together, representing the smallest fundamental unit of a chemical compound that take part in a chemical reaction.
3.Atomic mass = No. of protons + No. of neutrons.
4.Molecular mass: Sum of atomic masses of constituting element of a given molecule.
(a) Caustic Potash
(potassium hydroxide):
KOH
K+O+H=39+16+1=56u
(b) Baking Powder
(sodium bicarbonate):
NaHCO3Na+H+C+3×O=23+1+12+3×16=84u
(c) Lime Stone
(calcium carbonate):
CaCO3Ca+C+3×0=40+12+3×16=100u
(d) Magnisium chloride
MgCl2Mg+2×Cl=24+2×35.5=95u
(e) Common Salt
(sodium chloride)
NaCl
23+35.5=58.5u
4.0Key Advantages of NCERT Solutions for Class 9 Science Chapter 3 - Atoms and Molecules
Better Conceptual Clarity: The solutions are clearly explained so that students can better understand the fundamental concepts of atoms, molecules, and their properties.
Step-by-Step Explanation: The structured, step-by-step solutions provided can help students solve problems involving atomic structure, chemical formulas, and molecular mass calculations.
Thorough Exam Preparation: NCERT Solutions follows the CBSE curriculum and is ideal for exam preparation. It covers all the essential topics, helping students prepare better for exams.
Improved Problem-Solving Skills: Regular practice of these solutions develops students’ analytical and problem-solving skills, enabling them to comprehend chemical reactions and anticipate results effectively.
Practical Application: Knowledge of atoms and molecules aids students in appreciating the importance of these concepts in daily life, from comprehending common household chemicals to intricate industrial operations.
NCERT Solutions for Class 9 Science Other Chapters:-
The smallest unit of matter that still possesses an element's characteristics is an atom. It is made up of an electron-encircled nucleus that contains protons and neutrons.
Yes, you can easily study offline at any time by downloading the NCERT Solutions in PDF format from Allen’s website.
NCERT Solutions is a great tool, but to ensure you are ready, you should also use additional study materials, practice questions, and mock exams.
After attempting to answer the questions independently, students should consult NCERT Solutions for confirmation and explanation. Frequent use of these solutions enhances problem-solving abilities and helps with concept retention.