Chemistry (NTSE/Olympiad)  

3. Chemical Reactions

Points to Remember

♦ A chemical bond is the force of attraction which holds together the atoms in a molecule.
♦ An electrovalent bond is formed as a result of complete transfer of electron(s) from one atom to another.
♦ Atoms which can lose electrons and form positive ions are said to be electropositive.
♦ Atoms which can gain electrons and form negative ions are said to be electronegative.
♦ The total number of electrons lost or gained by an atom to attain the stable configuration of the nearest noble gas is known as the valency of the atom.
♦ The number of electrovalent bonds by an atom can form is called its electrovalency.
♦ Covalent bonds are formed by the mutual sharing of electrons between the combining atoms.
♦ Compounds containing covalent bonds are called covalent compounds.
♦ The. total number of electrons shared by a given atom in the formation of covalent bonds to attain the stable configuration of its nearest noble gas is known as its covalency.
♦ The force that holds the atoms closely together in a metal is known as the metallic bond.


NTSE Chemistry (Class X)

NTSE Chemistry (Class IX)


NTSE Physics Course (Class 9 & 10)

NTSE Chemistry Course (Class 9 & 10)

NTSE Geography Course (Class 9 & 10)

NTSE Biology Course (Class 9 & 10)

NTSE Democratic Politics Course (Class 9 & 10)

NTSE Economics Course (Class 9 & 10)

NTSE History Course (Class 9 & 10)

NTSE Mathematics Course (Class 9 & 10)