The correct answer is Only b. Key Points • Ionic bond: The bond formed between magnesium (Mg) and chlorine (Cl) in the compound MgCl_(2) is an ionic bond. This type of bond occurs due to the transfer of electrons from one atom to another. Magnesium, being a metal, loses two electrons to form a Mg^(2+) ion, while chlorine, being a non-metal, gains one electron to form two Cl^(-) ions. The electrostatic attraction between the oppositely charged ions forms the ionic bond. • Covalent bond: A covalent bond involves the sharing of electrons between atoms. However, in MgCl_(2), there is no sharing of electrons but a complete transfer of electrons, making the bond ionic. Hence, Option a is incorrect. • Coordinate covalent bond: A coordinate covalent bond involves one atom donating a lone pair of electrons to another atom. This is not the case in MgCl_(2), as the bond is purely ionic. Hence, Option c is incorrect. • Metallic bond: Metallic bonds occur in metals and involve a lattice of positive ions surrounded by a sea of delocalized electrons. In MgCl_(2), the bond is between a metal (magnesium) and a non-metal (chlorine), so metallic bonding does not occur. Hence, Option d is incorrect. • Thus, the correct answer is Only b. Additional Information • Ionic Bonds: • Ionic bonds are formed when one atom donates electrons to another atom, resulting in the formation of positively charged (cation) and negatively charged (anion) ions. The electrostatic force of attraction between these oppositely charged ions forms the ionic bond. • In the case of MgCl_(2), magnesium loses two electrons to form Mg^(2+), and each chlorine atom gains one electron to form two Cl^(-) ions. The resulting ionic compound has a strong lattice structure due to the electrostatic forces. • Covalent Bonds: • Covalent bonds involve the sharing of electrons between two non-metal atoms to achieve a stable electron configuration (octet rule). For example, in a water molecule (H_(2)O), oxygen shares electrons with hydrogen atoms. • Unlike ionic bonds, covalent bonds do not involve complete electron transfer but rather the sharing of electron pairs. • Metallic Bonds: • Metallic bonds are unique to metals and involve a lattice of metal ions surrounded by a "sea" of delocalized electrons. This bonding gives metals their characteristic properties, such as high electrical conductivity and malleability. • For example, metallic bonding is responsible for the properties of metals like copper (Cu) and aluminum (Al). • Coordinate Covalent Bonds: • In a coordinate covalent bond, one atom donates a lone pair of electrons to another atom. These bonds are commonly seen in complex compounds, such as ammonium ion (NH_(4)^(+)), where nitrogen donates a lone pair to hydrogen. • Coordinate covalent bonds often occur in coordination complexes or molecules with lone pairs of electrons available for donation. Important Points • Characteristics of Ionic Compounds: • Ionic compounds like MgCl_(2) have high melting and boiling points due to strong electrostatic forces of attraction. • They are generally soluble in water and other polar solvents. • In the solid state, ionic compounds are poor conductors of electricity, but in molten or dissolved states, they conduct electricity due to the movement of ions. • Examples of Ionic Compounds: • Sodium chloride (NaCl): Formed by the transfer of one electron from sodium to chlorine. • Calcium oxide (CaO): Formed by the transfer of electrons from calcium to oxygen.