Chemical Bonding And Molecular Structure printable pdf download

Chemical Bonding And Molecular Structure

CHAPTER-4

CHEMICAL BONDING AND MOLECULAR STRUCTURE

OCTET RULE- During a chemical reaction the atoms tend to adjust their

electronic arrangement in such a way that they achieve 8 e

in their outermost

electron. This is called octet rule.

CHEMICAL BOND- the chemical force which keeps the atoms in any molecule

together is called a chemical bond.

IONIC BOND- The columbic force of attraction which holds the appositively

charged ions together is called an ionic bond. An ionic bond is formed by the

complete transfer of one or more electrons from the atom of a metal to an atom of

non- metal.

LATTICE ENTHALPY- The molar enthalpy change accompanying the complete

separation of the constituent particles that compose of the solids (such as ions for

ionic solid, molecules for molecular solids) under standard conditions is called

lattice enthalpy (∆

). The lattice enthalpy is a positive quantity.

ELECTRO VALENCY: The number of electrons lost or gain by an atom of an

element is called as electrovalency.

The element which give up electrons to form positive ions are said to have positive

valency, while the elements which accept electrons to form negative ions are said to

have negative valency.

FORMATION OF AN IONIC BOND: It is favoured by, (i) the low ionisation

enthalpy of a metallic element which forms the cations, (ii) High electron gain

enthalpy of non- metallic element which forms the anions, (iii) Large lattice

enthalpy i.e; the smaller size and the higher charge of the atoms.

COVALENCY:The number of electrons which an atom contributes towards

mutual sharing during the formation of a chemical bond called its covalency in that

compound.

SINGLE COVALENT BOND: A covalent bond formed by the mutual sharing of

one pair of electrons is called a single covalent bond, or simply a single bond. A

single covalent bond is represented by a small line (−) between the two atoms.

Chemical Bonding And Molecular Structure