Question

Explain the formation of Ionic Compounds (e.g., \(NaCl\) or \(MgCl_2\)) and state their properties.

Hint:

Ionic compounds are formed by {transfer of electrons} and the {electrostatic attraction between oppositely charged ions}.

Answer 1

Concept: Ionic compounds are formed when electrons are transferred from one atom to another. This transfer results in the formation of cations (positive ions) and anions (negative ions). The strong electrostatic force of attraction between these oppositely charged ions forms an ionic bond.
Step 1:Formation of Sodium Chloride (\(NaCl\)) Sodium (\(Na\)) has one electron in its outermost shell, while chlorine (\(Cl\)) has seven electrons in its outer shell.

• Sodium loses one electron to form a positive ion: \[ Na \rightarrow Na^+ + e^- \]
• Chlorine gains one electron to form a negative ion: \[ Cl + e^- \rightarrow Cl^- \]

The oppositely charged ions attract each other to form the ionic compound: \[ Na^+ + Cl^- \rightarrow NaCl \]
Step 2:Formation of Magnesium Chloride (\(MgCl_2\)) Magnesium loses two electrons to form \(Mg^{2+\), and two chlorine atoms each gain one electron to form \(Cl^-\). \[ Mg \rightarrow Mg^{2+ + 2e^- \] \[ 2Cl + 2e^- \rightarrow 2Cl^- \] These ions combine to form magnesium chloride: \[ Mg^{2+ + 2Cl^- \rightarrow MgCl_2 \]
Step 3:Properties of Ionic Compounds

• They have high melting and boiling points.
• They are generally hard and brittle.
• They are soluble in water.
• They conduct electricity in molten state or in aqueous solution but not in solid state.