The learning institute Class 10 Science

  Allotropes of Carbon Allotropy:  The phenomenon in which the element exists in two or more different physical states with similar chemical properties are called Allotropy. Carbon has Three Main Allotropes Diamond:  In this, carbon, an atom is bonded to four other atoms of carbon forming three-dimensional structures. It is the hardest substance and an insulator. It is used for drilling rocks and cutting. It is also used for making jewellery. Graphite:  In this, each carbon atom is bonded to three other carbon atoms. It is a good conductor of electricity and used as a lubricant. Buckminster Fullerene:  It is an allotrope of the carbon-containing cluster of 60 carbon atoms joined together to form spherical molecules. It is dark solid at room temperature.

Electron Dot Structure:  Lewis structures are also known as Lewis dot structures or electron dot structures. These structures provide a picture of bonding in molecules in terms of the shared pairs of electrons and octet rule. In these structures elements symbol is in the centre and the dots around it shows the valence electrons. Formation of Hydrogen Molecule Atomic number of Hydrogen = 1 Number of valence electrons = 1 Formation of oxygen molecule Atomic number =8 Distribution of electrons  =[2,6] Valence electrons=6 Formation of Flourine molecule Atomic number =9 Distribution of electrons =[2,7] Valence electrons=7 Formation of oxygen molecule Atomic number =7 Distribution of electrons  =[2,5] Valence electrons=5 Formation of CH 4  Molecule Atomic number of Carbon = 6 Distribution of electrons= [2, 4] Number of valence electrons = 4 Atomic number of Hydrogen = 1 Number of valence electrons = 1 Formation of H2S Molecule Atomic number of Sulphur = 16  Distributi...

 Covalent bonds and ionic bonds The bond formed by mutual sharing of electron pairs between two atoms in a molecule is known as Covalent Bond. Types of Covalent Bond: Depending upon the number of shared electron pairs, the covalent bond can be classified into:  Single Covalent Bond  Double Covalent Bond  Triple Covalent Bond Single Covalent Bond: When a single pair of electrons are shared between two atoms in a molecule. For example; F 2 , Cl 2 , H 2  , methane etc. Double Covalent Bond: When two pairs of electrons are shared between two atoms in a molecule. For example; O 2 , CO 2  etc. Triple Covalent Bond: When three pairs of electrons are shared between two atoms in a molecule. For example; N 2  etc. Ionic bonds The bond formed by transfer of electron  between two atoms in a molecule is known as ionic Bond. Two atoms will make an ionic bond if they have different electronegativity values.  Difference between covalent compounds and ionic c...

 Carbon ................. The symbol for carbon is C. The atomic number of carbon is 6. Its electronic configuration is 2, 4. It requires 4 electrons to achieve the inert gas electronic configuration. It could gain four electrons forming C 4-  cation. But it would be difficult for the nucleus with six protons to hold on to ten electrons. It could lose four electrons forming C 4+  cations. But it requires a large amount of energy to remove four electrons. So it doesn't form ionic bond. Thus, carbon share its valence electrons with other carbon atoms or with atoms of other elements. The atoms of other elements hydrogen, oxygen, nitrogen, chlorine also form bond by sharing of electrons. ................. Versatile Nature of Carbon:   Carbon shows  two main properties which makes carbon to form large number of compounds. Catenation Tetravalent nature ........ ........ (i) Catenation:-  carbon link with carbon atom through covalent bonds to form long straight, b...

Electric current  class-10 Electric Current: The flow of electrons across a cross section of a conductor is known as Electric Current, Electric current is carried by moving electrons through a conductor.  What is electric current Or Define Electric current The rate of flow of electric charge through any section of a conductor is known as electric current. It is denoted by letter I.   What is the expression of electric current? If a net electric charge (Q) flows through a cross section of conductor in time t, then: Electric Current ( I ) = Net charge ( Q ) Time ( t ) Electric Current ( I ) = Net charge ( Q ) Time ( t ) Or,  I = Q t I = Q t Where I is electric current, Q is a net charge and t is a time in second. What is the SI unit of Electric current? The SI unit of Electric current is Ampere. Define 1 Ampere. if 1 coulomb of electric charge flows through a cross section for 1 second, it would be equal to 1 ampere. Electric Current ( I ) = Net charge ( Q ) Time ( t )...