Question

how does an ionic bond differ from a covalent bond ? illustrate with one example of each type of bond

Answer 1

Ionic bonds generally formed by transfer of electrons.
For eg. NaCl
Na has +1 oxidation state and Cl has -1 oxidation state. As they both combined in order to complete their octet.

Covalent bonds are formed by sharing pairs of electron.
For eg. CO2.
Carbon shares pairs of electron with oxygen atoms and combined in order to complete it's octet.

Hope you get your answer.

Answer 2

HI !

Ionic compounds are those which are formed by transferring of electrons.
Certain elements form compounds with other element , by either losing electrons electrons , or  by taking electrons.
Due to the exchange of ions , these compounds contain cations/anions in them.
And thus , they have high melting and boiling points

Eg :-

NaCl 

Sodium(Na) has one electron in its valence shell and chlorine also needs one electron to attain stability(atomic no: of chlorine is 17), Hence chlorine gets the one electron from sodium , which needs to lose one electron to attain noble state , and forms ionic compound.
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Covalent compounds are formed by sharing of electrons. Elements form compounds by sharing electrons with other element 
They have low melting and boiling points .

Eg:-
CO₂
carbon shares 4 electrons with 2 atoms of oxygen , which need 2 electrons each.