Class 9th ICSE

Chapter 5. The Periodic Table

March 3, 2021January 1, 2021 by ap-admin

Periodic Classification of Elements – History of Periodic Table * Dobereiner’s Law of Traids: In a traid, the atomic mass of the middle element is equal to the arithmetic mean of the atomic masses of the other two. * Newlands law of octaves: When elements are arranged in increasing order of their atomic weights, the ... Read more

Chapter 4. Atomic Structure and Chemical Bonding

March 3, 2021January 1, 2021 by ap-admin

Structure of Atoms – Structure of an Atom * An atomic number is the number of protons in an atom. * The arrangement of electrons in various energy levels of an atom is known as electronic configuration. * The maximum number of electrons in any energy level of the atom is given by 2n2. * ... Read more

Chapter 3. Water

February 6, 2021January 1, 2021 by ap-admin

Composition of Water * The chemical formula of water was established by S. Cannizzarro as H2O. * The process of decomposing water into its constituent elements called electrolysis of water. * Hydrogen and oxygen combine in the ratio of 2:1 by volume to from water. * The gravimetric or mass ratio of hydrogen to oxygen ... Read more

Chapter 2. Chemical Changes and Reactions

March 3, 2021January 1, 2021 by ap-admin

Physical and Chemical Changes – Physical and Chemical Changes * Change is all around us and happening constantly. Some changes are Physical and some are chemical. * Some changes affect only the physical properties of the substance that is undergoing change. Physical include things like shape, size, colour and state of matter. Physical changes are ... Read more

Chapter 1. The Language Of Chemistry

February 6, 2021January 1, 2021 by ap-admin

Atoms and Molecules • Matter is made of tiny indivisible particles. • In any chemical reaction, the total mass of the substance before and after the reaction is the same although its matter undergoes a physical change. • Molecule is the combined state of atoms. • Number of atoms constituting a molecule is atomicity. • ... Read more

Chapter 8. Electricity and Magnetism

March 22, 2021January 1, 2021 by ap-admin

Electricity and Circuit – Electricity Conductors and Insulators * Materials that allow electricity to pass through them are called conductors. * Materials that do not allow electricity to pass through there are called insulators. * We need conducting materials to make electrical circuits. * Air is an insulator * All electrical appliances are covered with ... Read more

Chapter 7. Sound

March 9, 2021January 1, 2021 by ap-admin

Sound - Production and Propagation of Sound * Sound is form of energy that produces the sensation of hearing in our ears. * Sound is produced due to the vibration of objects. * Intensity of sound is the amount of sound energy incident per unit time per unit area. * Sound propagates through a medium. ... Read more

Chapter 6. Light

March 22, 2021January 1, 2021 by ap-admin

Reflection of Light * Light travels in straight lines. * A shiny or polished surface, such as a mirror, can change the direction of incident light. * The bouncing of light by any smooth surface like a mirror, back into the same medium, is called reflection of light. * The likeness of light by an ... Read more