Question

what is ionic compound ? list two properties of these compound

Answer 1

The compounds which have bonds formed by loss and gain of electrons are called ionic compounds or electrovalent compound and the bond formed is know as ionic bond or electrovalent bond. Two properties of Ionic compounds :
 (i) Ionic compounds are hard and brittle. 
(ii) Ionic compounds have high melting and boiling points.

Answer 2

Answer: Ionic compound is formed by the transfer of electrons.

For formation of a neutral ionic compound, the charges on cation and anion must be balanced. The cation is formed by loss of electrons by metals and anions are formed by gain of electrons by non metals.  

$Na^++Cl^-\rightarrow NaCl$

$[Na]=1s^22s^22p^63s^1$

Sodium atom will loose one electron to gain noble gas configuration and form sodium cation with +1 charge.

$[Na^+]=1s^22s^22p^63s^0$

Chlorine atom has oxidation number of -1.

$[Cl]=1s^22s^22p^63s^23p^5$

Chlorine atom will gain one electron to gain noble gas configuration and form chloride ion with -1 charge.

$[Cl^-]=1s^22s^22p^63s^23p^6$

The cations and anions being oppositely charged attract each other through strong coloumbic forces and form an ionic bond.

Properties of ionic compounds:

1) They are hard and crystalline due to regular arrangement of ions.

2) They have high melting points due to strong electrostatic attractions.