Question
Which statement best describes metallic bonding?
A. Electrostatic attractions between oppositely charged ions
B. Electrostatic attractions between a lattice of positive ions and delocalized electrons
C. Electrostatic attractions between a lattice of negative ions and delocalized protons
D. Electrostatic attractions between protons and electrons
▶️Answer/Explanation
B
Metallic bonding is the electrostatic attraction between a lattice of positive metal ions and a sea of delocalized electrons.
Question
Which substance does not conduct electricity?
A. Solid zinc
B. Molten zinc
C. Solid zinc chloride
D. Molten zinc chloride
▶️Answer/Explanation
C
Zinc chloride is made up of positive zinc ions and negative chloride ions held together by electrostatic attractions in a 3–D lattice. Zinc chloride does not conduct electricity as a solid as these ions are not free to move around, hence it doesn’t have free electrons/ions to conduct electricity.
Rest others have free electrons/ions which can conduct electricity.
Question
Which substance is made up of a lattice of positive ions and free moving electrons?
A. Graphite
B. Sodium chloride
C. Sulfur
D. Sodium
▶️Answer/Explanation
D
Sodium metal has a kind of a lattice arrangement in which the metal exists in positively charged atoms. They do this so because sodium has only one electron in its outermost orbital. Sodium atoms lose an electron each and these electrons are delocalized over the entire lattice. So, they are free to move. We know that if any metal possesses free electrons, then they are good conductors of electricity. They do so because the free electrons act as a carrier for the electric charge.
Question
Which particles are responsible for electrical conductivity in metals?
A. Anions
B. Cations
C. Electrons
D. Protons
▶️Answer/Explanation
C
If any metal possesses free electrons, then they are good conductors of electricity. They do so because the free electrons act as a carrier for the electric charge.
Question
Which particles are responsible for the conduction of electricity in molten Aluminium?
A. Cations
B. Anions
C. Electrons
D. Protons
▶️Answer/Explanation
C
Molten metal will still conduct electricity but the carriers in metal will be electrons only. Hence, electrons only are responsible for the conduction of electricity molten Aluminium.
Question
A substance has the following properties:
What is the most probable structure of this substance?
A. Network covalent
B. Polar covalent molecule
C. Ionic lattice
D. Metallic lattice
▶️Answer/Explanation
A
Network covalent structures have consistent physical properties: namely, that they have high melting points, they are hard, they are brittle, and in general they do not conduct electricity (in solid or molten state both). One exception to this is graphite, which can conduct electricity due to the presence of delocalized electrons.