Tag: class 9
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Class 9th – STRUCTURE OF ATOM (Models)
DIFFERENT MODEL OF ATOM PROPOSED BY DIFFERENT SCIENTIST MODEL PROPOSED BY J.J THOMSON According to him, the atom consist of positively charged sphere and all the electrons are embedded in it. The positive and the negative charge are equal in number, thus making the atom neutral . POSTULATES: Atom consist of positive charge all over…
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Class 9th – STRUCTURE OF ATOM (Atomic & Mass Number)
We have already discussed the model of an atom and also were the subatomic particles are present inside an atom. Atomic Number As we know that the protons are present inside the nucleus , so the atomic no. of an element is defined as the number of protons present in an atom. Therefore, atomic number…
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Class 9th – STRUCTURE OF ATOM (Subatomic Particles)
We have already discussed in the chapter of atoms and molecules, how atoms are made and how molecules are made. In this chapter we will study in detail about the structure of Atom. An atom is made up of 3 sub-atomic particles; Protons. Electrons. Neutrons. PROTONS The discovery of proton was done by E. Goldstein.…
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Class 9th – VALENCY OF IONS
Valency of ion is equal to the charge of the ions. Cations carry positive charge whereas Anions carry negative charge. When the valency is 1 for cations, they are called as Monovalent Cations. When the valency is 2 for the cations, they are called as divalent cations. When valency is 3 for the cations, they…
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Class 9th – CHEMICAL FORMULAE
It determines the composition of a molecule of the Compound, with the symbols of the elements present in it. When a metal and a non metal combine it result in the formation of Ionic Compound. The compounds that are formed by Ions. The ions present in KNO3 (Potassium nitrate) are K⁺ & NO3ˉ Rules for…
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Class 9th – ATOMIC MASS OF AN ELEMENT
Atoms of elements are very small. To understand about atomic mass, it is a need to know about Carbon-12. Carbon-12 can be stated as no. of protons= 6 & no. of neutrons= 6 thus making it as 12. Carbon-12 atoms has been made as atomic mass of exactly 12 atomic mass unit. Earlier the unit…
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Class 9th – ATOMS AND MOLECULES
Atoms are indivisible particles which cannot be divided further. The Indian philosopher Kanada was the first to call that matter are made up of small particles called Parmanu. John Dalton called matter is made up of small particles called Atom. LAWS OF CHEMICAL COMBINATION: LAW OF CONSERVATION OF MASS LAW OF CONSTANT PROPORTION LAW OF…
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Class 9th – POTENTIAL ENERGY
The energy possessed by a body due to its position or configuration is called Potential Energy. EXAMPLES OF POTENTIAL ENERGY A stretched rubber band possesses potential energy. A raised object possesses potential energy. Water that is stored in the dam possesses potential energy.
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Class 9th – KINETIC ENERGY
Any object that is having the capability to do work possesses energy. The energy possessed by a moving object is called Kinetic Energy. The energy can be transferred from one form to another, i.e. an object S does the work on object K, if an object S which does the work looses energy and the…
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Class 9th – ENERGY
The capacity of a body to do work is called the energy. SI Unit of energy is same that of work i.e. Joule. Energy is Scalar quantity. 1kJ = 1000J