Assessment Tools
Assign | Assess | Analyse
Quick Quiz
Objective Assessment
Question Bank
List Of Questions With Key, Aswers & Solutions
Back To Learn
Re – Learn
Go Back To Learn Again
Level: Chapter
Chapter Level Content
Physical and Chemical Changes | Assess
QUADRILATERALS | Study
REPRODUCTION IN ANIMALS | Assess
REPRODUCTION IN ANIMALS | Study
Respiration in Organisms | Study
STRUCTURE OF THE ATOM | Assess
STRUCTURE OF THE ATOM | Study
THE FUNDAMENTAL UNIT OF LIFE | Assess
The Triangle and its Properties | Assess
QUADRILATERALS | Study
Mind Map Overal Idea Content Speed Notes Quick Coverage Quadrilateral Any closed polygon with four sides, four angles and four vertices are called Quadrilateral. It could be regular or irregular. (Sroll down to continute till the end …) Study Tools Audio, Visual & Digital Content Quadrilateral Quadrilateral is a closed figure with four sides. Characteristics readmore
Mind Map
Overal Idea
Content
Speed Notes
Quick Coverage
Quadrilateral
Any closed polygon with four sides, four angles and four vertices are called Quadrilateral. It could be regular or irregular. (Sroll down to continute till the end …)
Study Tools
Audio, Visual & Digital Content
Quadrilateral
Quadrilateral is a closed figure with four sides.
Characteristics of a quadrilateral
Angle Sum Property of a Quadrilateral:
Qudrilateral is a four sided closed figure.
Sum of all angles of a quadrilateral is 360°.
Types Of Quadrilaterals
Classification of quadrilaterals Quadrilaterals are broadly classified into three categories as:
(i) Kite
(ii) Trapezium
(ii) Parallelogram
Kite:
(i) Kite has no parallel sides
(ii) Kite has a pair of equal adjacent sides.
(ii) It is not a parallelogram
Characteristics Of Kite:
Perimeter Of Square
Area Of Kite
Trapezium:
Trapezium is a quadrilateral with the following characteristics:
(i) One pair of opposite sides is parallel to each other.
(ii) The other pair of opposite sides may not be parallel to each other.
Characteristics Of Trapezium
(i) Sum of all angles of a quadrilateral is 360°.
(ii) One pair of opposite sides is parallel to each other.
(iii) The other pair of opposite sides need not be parallel to each other.
Types Of Trapezium:
Quadrilaterals are broadly classified into two categories as:
(i) Isosceles Trapezium.
(ii) Scalene Trapezium.
(i) Right Trapezium.
Isosceles Trapezium:
Isosceles Trapezium is a quadrilateral with the following characteristics:
(i) One pair of opposite sides is parallel to each other.
(ii) The other pair of opposite sides are equal.
(iii) The other pair of opposite sides need not be parallel to each other.
Isosceles Trapezium is a trapezium with the following characteristics:
(i) One pair of opposite sides is parallel to each other.
(ii) The other pair of opposite sides are equal.
(iii) The other pair of opposite sides need not be parallel to each other.
Characteristics Of Isosceles Trapezium
(i) Sum of all angles of a quadrilateral is 360°.
(ii) One pair of opposite sides is parallel to each other.
(iii) The other pair of opposite sides are equal.
(iv) The other pair of opposite sides need not be parallel to each other.
Scalene Trapezium:
- Scalene trapezium: Classified by the length of the legs or the measurement of their angles.
Characteristics Of Scalene Trapezium
Right Trapezium:
- Right trapezium: Has one pair of parallel sides and one pair of right angles.
Characteristics Of Right Trapezium
Perimeter Of Trapezium
Area Of Trapezium
Parallelogram:
Parallelogram is a quadrilateral with the following characteristics:
(i) Two pairs of opposite sides are parallel to each other.
(ii) Two pairs of opposite sides are equal in length.
Characteristics of a parallelogram
(i) Sum of all angles of a Parallelogram is 360°.
(ii) Two pairs of opposite sides are parallel to each other.
(ii) Two pairs of opposite sides are equal in length.
(ii) Two pairs of opposite angles are equal.
(iii) Diagonals bisect each other.
(iv) Diagonals need not be equal to each other.
(v) Diagonals divide it into two congruent triangles.
Types Of Parallelogram
Parallelograms are broadly classified into three categories as:
(i) Rectangle
(ii) Rhombus
(iii) Square
Perimeter Of Parallelogram
Area Of Parallelogram
Rectangle:
Rectangle is a quadrilateral with the following characteristics:
(i) Two pairs of opposite sides are parallel to each other.
(ii) Two pairs of opposite sides are equal in length.
(iii) All four angles are right angles. (each angle is 90 o).
Characteristics Of Rectangle
(i) Sum of all angles of a quadrilateral is 360°.
(ii) Two pairs of opposite sides are parallel to each other.
(ii) Two pairs of opposite sides are equal in length.
(iii) All four angles are right angles. (each angle is 90 o).
(iii) Diagonals bisect each other.
(iv) Diagonals are equal to each other.
(v) Diagonals of a rectangle divide it into two congruent triangles.
Conclusions:
- Every Rectangle is a Parallelogram. But Every Parallelogram need not to be a Rectangle.
Condition for a rhombus to be a square:
If all four angles of a parallelogram are right angles. (each angle is 90 o), the parallelogram becomes a Rectangle.
Perimeter Of Rectangle
Area Of Recatangle
Rhombus:
Rhombus is a quadrilateral with the following characteristics:
(i) Two pairs of opposite sides are parallel to each other.
(ii) All four sides are equal in length.
Characteristics Of Rhombus
(i) Sum of all angles of a quadrilateral is 360°.
(ii) Two pairs of opposite sides are parallel to each other.
(ii) All four sides are equal in length.
(ii) Two pairs of opposite angles are equal.
(iii) Diagonals bisect each other.
(iv) Diagonals need not be equal to each other.
(v) Diagonals divide a Rhombus into two congruent triangles.
Conclusions:
- Every Rhombus is a Parallelogram. But Every Parallelogram need not to be a Rhombus.
Condition for a rhombus to be a square:
If all the sides of a parallelogram are equal, the parallelogram becomes a Rhombus.
Perimeter Of Rhombus
Area Of Rhombus
Square:
Square is a quadrilateral with the following characteristics:
(i) Two pairs of opposite sides are parallel to each other.
(ii) All four sides are equal in length.
(iii) All four angles are right angles. (each angle is 90 o).
Characteristics Of Square
(i) Sum of all angles of a quadrilateral is 360°.
(ii) Two pairs of opposite sides are parallel to each other.
(iii) All four sides are equal in length.
(iv) All four angles are right angles. (each angle is 90 o).
(v) Diagonals bisect each other.
(vi) Diagonals need not be equal to each other.
(vii) Diagonals divide a Rhombus into two congruent triangles.
Conclusions:
- Every square is a Rhombus. But Every Rhombus need not to be a square.
Condition for a rhombus to be a square:
If all the angles of a rhombus are right angles (euqal to 90o), the rhombus becomes a square.
2. Every Square is a prallelogram. But Every prallelogram need not to be a square.
Condition for a prallelogram to be a square:
(i) If all the angles of a parallelogram are right angles (euqal to 90o), and all the sides of a parallelogram are equal in length, the parallelogram becomes a square.
3. Every Square is a rectangle. But Every Rectangle need not to be a square.
Condition for a Rectangle to be a square:
If all the sides of a Rectangle are equal in length, the Rectangle becomes a square.
If all the sides of a parallelogram are equal, the parallelogram becomes a Rhombus.
Perimeter Of Square
Area Of Square
Important Points To Remember
- The diagonals of a parallelogram are equal if and only if it is a rectangle.
- If a diagonal of a parallelogram bisects one of the angles of the parallelogram then it also bisects the opposite angle.
- In a parallelogram, the bisectors of any two consecutive angles intersect at a right angle.
- The angle bisectors of a parallelogram form a rectangle.
Mid Point Theorem
A line segment joining the mid points of any two sides of a triangle is parallel to the third side and length of the line segment is half of the parallel side.
Converse Of Mid Point Theorem
A line through the midpoint of a side of a triangle parallel to another side bisects the third side.
Intercept Theorem
If there are three parallel lines and the intercepts made by them on one transversal are equal then the intercepts on any other transversal are also equal.
Angle Sum Property of a Quadrilateral
The sum of the four angles of a quadrilateral is 360°
If we draw a diagonal in the quadrilateral, it divides it into two triangles.
And we know the angle sum property of a triangle i.e. the sum of all the three angles of a triangle is 180°.
The sum of angles of ∆ADC = 180°.
The sum of angles of ∆ABC = 180°.
By adding both we get ∠A + ∠B + ∠C + ∠D = 360°
Hence, the sum of the four angles of a quadrilateral is 360°.
Example
Find ∠A and ∠D, if BC∥ AD and ∠B = 52° and ∠C = 60° in the quadrilateral ABCD.
Solution:
Given BC ∥ AD, so ∠A and ∠B are consecutive interior angles.
So ∠A + ∠B = 180° (Sum of consecutive interior angles is 180°).
∠B = 52°
∠A = 180°- 52° = 128°
∠A + ∠B + ∠C + ∠D = 360° (Sum of the four angles of a quadrilateral is 360°).
∠C = 60°
128° + 52° + 60° + ∠D = 360°
∠D = 120°
∴ ∠A = 128° and ∠D = 120 °.
Types of Quadrilaterals
S No. Quadrilateral Property Image 1. Kite a. No Parallel Sides
b. Two pairs of adjacent sides are equal.2. Trapezium One pair of opposite sides is parallel. 
3. Parallelogram Both pairs of opposite sides are parallel. 
3. Rectangle a. Both the pair of opposite sides are parallel.
b. Opposite sides are equal.c.
All the four angles are 90°.
4. Square a. All four sides are equal.
b. Opposite sides are parallel.
c. All the four angles are 90°.
5. Rhombus a. All four sides are equal.
b. Opposite sides are parallel.
c. Opposite angles are equal.d.
Diagonals intersect each other at the centre and at 90°.
Remark: A square, Rectangle and Rhombus are also a parallelogram.
Properties of a Parallelogram
Theorem 1: When we divide a parallelogram into two parts diagonally then it divides it into two congruent triangles.
∆ABD ≅ ∆CDB
Theorem 2: In a parallelogram, opposite sides will always be equal.
Theorem 3: A quadrilateral will be a parallelogram if each pair of its opposite sides will be equal.
Here, AD = BC and AB = DC
Then ABCD is a parallelogram.
Theorem 4: In a parallelogram, opposite angles are equal.
In ABCD, ∠A = ∠C and ∠B = ∠D
Theorem 5: In a quadrilateral, if each pair of opposite angles is equal, then it is said to be a parallelogram. This is the reverse of Theorem 4.
Theorem 6: The diagonals of a parallelogram bisect each other.
Here, AC and BD are the diagonals of the parallelogram ABCD.
So the bisect each other at the centre.
DE = EB and AE = EC
Theorem 7: When the diagonals of the given quadrilateral bisect each other, then it is a parallelogram.
This is the reverse of the theorem 6.
The Mid-point Theorem
1. If a line segment joins the midpoints of the two sides of the triangle then it will be parallel to the third side of the triangle.
If AB = BC and CD = DE then BD ∥ AE.
2. If a line starts from the midpoint of one line and that line is parallel to the third line then it will intersect the midpoint of the third line.
If D is the midpoint of AB and DE∥ BC then E is the midpoint of AC.
Example
Prove that C is the midpoint of BF if ABFE is a trapezium and AB ∥ EF.D is the midpoint of AE and EF∥ DC.
Solution:
Let BE cut DC at a point G.
Now in ∆AEB, D is the midpoint of AE and DG ∥ AB.
By midpoint theorem, G is the midpoint of EB.
Again in ∆BEF, G is the midpoint of BE and GC∥ EF.
So, by midpoint theorem C is the midpoint of BF.
Hence proved.
Hindi Version Key Terms
Topic Terminology
Term
Important Tables
Table:
.
Assessments
Test Your Learning
Advanced Tools For Study Assess Interact REPRODUCTION IN ANIMALS | Assess
Assessment Tools
Assign | Assess | Analyse
Quick Quiz
Objective Assessment
Question Bank
List Of Questions With Key, Aswers & Solutions
Back To Learn
Re – Learn
Go Back To Learn Again
REPRODUCTION IN ANIMALS | Study
Mind Map Overal Idea Content Speed Notes Quick Coverage Reproduction is a process in which the organisms produce the young ones of their own kind. There are two modes by which animals reproduce. These are: (i) Sexual reproduction, and (ii) Asexual reproduction (Scroll down till end of the page) Study Tools Audio, Visual & Digital readmore
Mind Map
Overal Idea
Content
Speed Notes
Quick Coverage
Reproduction is a process in which the organisms produce the young ones of their own kind. There are two modes by which animals reproduce.
These are: (i) Sexual reproduction, and (ii) Asexual reproduction (Scroll down till end of the page)
Study Tools
Audio, Visual & Digital Content
Sexual Reproduction
Reproduction resulting from the fusion of male and female gametes is called sexual reproduction.
The reproductive organs in the female include ovaries, oviducts and uterus.
The reproductive organs in male include testes, sperm ducts and penis.
The ovary produces female gametes called ovum and the testes produce male gametes called sperms. The fusion of ovum and sperm is called fertilization.
zygote: The fertilized egg is called a zygote.
internal fertilization: Fertilization that takes place inside the female body is called internal fertilization. This is observed in human beings and other animals such as hens, cows and dogs.
external fertilization: Fertilization that takes place outside the female body is called external fertilization. This is observed in frogs, fish, starfish, etc.
The zygote divides repeatedly to give rise to an embryo. The embryo gets embedded in the wall of the uterus for further development.
The stage of the embryo in which all the body parts are identifiable is called foetus.
Animals such as human beings, cows and dogs which give birth to young Ones.
Asexual Reproduction: The type of reproduction in which only a single parent is involved is called asexual reproduction. The transformation of the larva into adult through drastic changes is called Asexual Reproduction
budding: In hydra, new individuals develop from buds. This method of asexual reproduction is called budding.
binary fission.: Amoeba reproduces by dividing itself into two. This type of asexual reproduction is called binary fission.
Hindi Version Key Terms
Topic Terminology
Term
Important Tables
Table:
.
Assessments
Test Your Learning
Advanced Tools For Study Assess Interact Respiration in Organisms | Study
Mind Map Overal Idea Content Speed Notes Quick Coverage Respiration is essential for survival of living organisms. It releases energy from the food. The oxygen we inhale is used to breakdown glucose into carbon dioxide and water. Energy is released in this process. The breakdown of glucose occurs in the cells of an organism (cellular readmore
Mind Map
Overal Idea
Content
Speed Notes
Quick Coverage
Respiration is essential for survival of living organisms.
It releases energy from the food.
The oxygen we inhale is used to breakdown glucose into carbon dioxide and water.
Energy is released in this process.
The breakdown of glucose occurs in the cells of an organism (cellular respiration) (Scroll down till end of the page)
Study Tools
Audio, Visual & Digital Content
During heavy exercise when the supply of oxygen to our muscle cells is insufficient, food breakdown is by anaerobic respiration (without oxygen)
Types of Respiration:
External respiration also known as breathing refers to a process of inhaling oxygen from the air into the lungs and expelling carbon dioxide from the lungs to the air.
Exchange of gases both in and out of the blood occurs simultaneously.
Internal Respiration: Process in which food is broken down in body cells.
Internal respiration is further classified into two types as aerobic respiration and anaerobic respiration
(a) Aerobic Respiration: Aerobic respiration takes place in the presence of oxygen. Carbon dioxide and water are the end products of aerobic respiration. respiration happens in most of the organisms.
(b) Anaerobic Respiration: Anaerobic respiration takes place in the absence of oxygen.
Anaerobic respiration usually happens in most of the microbes.
Alcohol and carbon dioxide are formed at the end of anaerobic respiration.
In some cases, lactic acid is formed at the end of anaerobic respiration.
Respiration in Plants: Leaves have pores called stomata for gaseous exchange by diffusion.
Stems have openings called lenticels for gaseous exchange by diffusion.
Roots have stomatal pores for gaseous exchange of oxygen dissolved in soil water.
Respiration in Animals: Respiration in animals vary according to their character like:
Earthworm: Earthworms respire through their skin.
Insect: Insects respire through entire body surface.
Fish: Fishes respire through their gills.
Frogs: Frogs respire through their thin, moist and smooth skin when in water and by lungs when on the land.
Respiration in Humans: Inhaled air passes through nostrils into nasal cavity and then into lungs through windpipe.
Breathing is a part of the process of respiration during which an organism takes in the oxygen-rich air and gives out air rich in carbon dioxide.
The respiratory organs for the exchange of gases vary in different organisms.
During inhalation, our lungs expand and then come back to the original state as the air moves out during exhalation.
Increased physical activity enhances the rate of breathing.
In animals like cow, buffalo, dog and cat the respiratory organs and the process of breathing are similar to those in humans.
Hindi Version Key Terms
Topic Terminology
Term
Important Tables
Table:
.
Assessments
Test Your Learning
Advanced Tools For Study Assess Interact STRUCTURE OF THE ATOM | Assess
Assessment Tools
Assign | Assess | Analyse
Quick Quiz
Objective Assessment
Question Bank
List Of Questions With Key, Aswers & Solutions
Back To Learn
Re – Learn
Go Back To Learn Again
STRUCTURE OF THE ATOM | Study
Mind Map Overal Idea Content Speed Notes Quick Coverage Atoms are the basic building blocks of matter. Different kinds of matter contain different kinds of atoms present in them. Protons were discovered by Ernest Rutherford, in his famous gold foil experiment. Electrons were discovered by J.J. Thomson, in his cathode ray tube experiment. Neutrons were readmore
Mind Map
Overal Idea
Content
Speed Notes
Quick Coverage
Atoms are the basic building blocks of matter.
Different kinds of matter contain different kinds of atoms present in them.
Protons were discovered by Ernest Rutherford, in his famous gold foil experiment.
Electrons were discovered by J.J. Thomson, in his cathode ray tube experiment.
Neutrons were discovered by James Chadwick. (Scroll down till end of the page)
Study Tools
Audio, Visual & Digital Content
Charged Particles in Matter
- Whenever we rub two objects together, they become electrically charged.
- This is because atoms contain charged particles in them.
- Therefore, atoms can be divided further into particles i.e proton, electron and neutron.
Atoms consist of an equal number of protons and electrons.
Protons exist in the interiors of the atom and electrons exist in the exteriors of the atom. Therefore, electrons can be removed from an atom.
Since electrons exist in the exteriors of the atom they can be removed from an atom.
Dalton’s Atomic Theory
The postulates of the atomic theory by John Dalton
- The matter is made up of tiny particles called Atoms that cannot be divided.
- Atoms are never formed or destroyed during a chemical reaction.
- Atoms of an element exhibit the same nature.
- Atoms of the same element have equal size, mass and they exhibit similar chemical properties.
- Atoms of different elements exhibit variant chemical properties.
- Atoms form compounds by combining in a ratio of whole numbers.
- A compound contains molecules in which a constant number and types of atoms are present.
Failure of Dalton’s Atomic Theory
Dalton suggested that atoms can neither be created nor destroyed and are indivisible.
But the discovery of electrons and protons in atoms disproved this aspect of Dalton’s theory.
Thomson’s Model of an Atom
According to J.J. Thomson, the structure of an atom can be compared to Christmas pudding.
According to this model the electrons are present inside a positive sphere.
An atom is composed of a positively charged sphere in which electrons are embedded.
Atoms are neutral as the positive and negative charges are equal in number.
Rutherford’s Model of an Atom
Rutherford’s Experiment
Rutherford experimented by passing alpha rays through a thin gold foil.
He expected that the gold atoms would deflect the Alpha particles.
Observations Inferences Alpha particles which had high speed moved straight through the gold foil Atom contains a lot of empty space Some particles got diverted a by small angles Positive charges in the atom are not occupying much of its space Only one out of 12000 particles bounced back The positive charges are concentrated over a particular area of the atom. Based on his experiment Rutherford gave the nuclear model of an atom as the following.
Rutherford’s Atomic Model
Rutherford’s Atomic Model is known as Planetary Atomic Model and Nuclear Atomic Model.
According to Rutherford’s Atomic Model:
- Atoms contain a lot of unoccupied space
- The center of the atom is highly positive , Rutherford named it as nucleus
- The atom contains an equal amount of positive and negative charges.
Nucleus of Atom
The nucleus is located at the center of the atom.
All the mass of the atom is because of the nucleus.
The electrons revolve around the nucleus in circular parts which called Orbits
The size of an atomic nucleus is much smaller than its atom.
Drawbacks of the Nuclear Atomic Model
The Rutherford’s Atomic Model failed to explain how an atom remains stable despite having positive and negative charges present in it.
Maxwell’s theory of radiation if any charged particle moves in a circular motion it radiates energy.
So, if electrons move in a circular motion around the nucleus they should radiate some energy as a result this decreases at the speed of the electrons. As a result, they would fall into the nucleus and the nucleus should collapse because of its high positive charge.
But it is not happening because the matter is not collapsing.
Nucleons: The subatomic particles present in the nucleus are collectively called Nucleons. Protons and Neutrons are nucleons.
Bohr’s Model of an Atom
Bohr Atomic Model states as the following:
- Electrons revolve around the nucleus in particular circular paths, called orbits.
- The electrons do not emit any energy while moving in their orbits.
- The orbits are also called Energy Levels.
- Energy Levels or Orbits are represented by using letters or numbers as shown in the figure.
Neutron:
J. Chadwick discovered Neutron, a subatomic particle of an atom.
Neutron carries no charge.
Subatomic Particles of Atom
Electrons Electron carry a negative charge Protons Protons carry a positive charge Neutrons Neutrons are neutral Electronic Configuration: The distribution of electrons in different shells or orbits is called Electronic Configuration.
- If Orbit number = n
- Then number of electrons present in an Orbit = 2n2
- So, for n =1
- Maximum electrons present in shell – K = 2 * (1)2 = 2
- The outermost shell can contain at most 8 electrons.
- The shells in an atom are filled in sequence.
- Thus, until the inner shells of an atom are filled completely the outer shells cannot contain any electrons.
Valency
- Valence Electrons – Electrons existing in the outermost orbit of an atom are called Valence Electrons.
- The atoms which have completely filled the outermost shell are not very active chemically.
- The valency of an atom or the combining capacity of an atom is given by the number of elements present in the outermost shell.
- For Example, Helium contains two electrons in its outermost shell which means its valency is two. In other words, it can share two electrons to form a chemical bond with another element.
- What happens when the outermost shell contains a number of electrons that are close to its maximum capacity?
Valency in such cases is generated by subtracting the number of electrons present in the outermost orbit from octet (8). For example, oxygen contains 6 electrons in its outermost shell. Its valency is calculated as: 8 – 6 = 2. This means oxygen needs two electrons to form a bond with another element.
Representation Element:
Atomic Number of an Element
Atomic Number (Z) = Number of protons in an atom
Mass Number of an Element
Mass Number = Number of protons + Number of neutrons
Isotopes
- The atoms of an element can exist in several forms having similar atomic numbers but varying mass numbers.
- Isotopes are pure substances.
- Isotopes have a similar chemical nature.
- Isotopes have distinct physical characteristics.
Use of Isotopes:
1. The fuel of Nuclear Reactor – Isotope of Uranium
2. Treatment of Cancer – Isotope of Cobalt
3. Treatment of Goiter – Isotope of Iodine
Example: Consider two atomic species namely U and V. Are they isotopes?
U V Protons 5 5 Neutrons 5 6 Mass Number 5 + 5 = 10 5 + 6 = 11 Atomic Number 5 5 From the above example, we can infer that U and V are isotopes because their atomic number is the same.
Isobars
The atoms of several elements can have a similar mass number but distinct atomic masses. Such elements are called Isobars.
Hindi Version Key Terms
Topic Terminology
Term
Important Tables
Table:
.
Assessments
Test Your Learning
Advanced Tools For Study Assess Interact THE FUNDAMENTAL UNIT OF LIFE | Assess
Assessment Tools
Assign | Assess | Analyse
Quick Quiz
Objective Assessment
Question Bank
List Of Questions With Key, Aswers & Solutions
Back To Learn
Re – Learn
Go Back To Learn Again
The Triangle and its Properties | Assess
Assessment Tools
Assign | Assess | Analyse
Quick Quiz
Objective Assessment
Question Bank
List Of Questions With Key, Aswers & Solutions
Back To Learn
Re – Learn
Go Back To Learn Again
