What are ionic compounds? List two properties of these compounds.

An ionic compound is a compound composed of ions that are held together by electrostatic forces termed as ionic bonding. 

 The compound is overall neutral but consists of positively charged ions called cations and negatively charged ions called anions.

 example sodium chloride, it consists of Na⁺ cations and Cl^- anions.

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

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

A chlorine atom has an oxidation number of -1.

[Cl]= 1s² 2s² 2p⁶ 3s² 3p⁵

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

[Cl^-]= 1s² 2s² 2p⁶ 3s² 3p⁶

 Thus, a strong Electrostatic force exists between them.

 1) Ionic Compounds are hard and crystalline due to the regular arrangement of ions. 

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