GED Science TestPhysical ScienceHard
A chemist is analyzing a newly synthesized compound. They determine that the compound has a very high melting point, is a good electrical conductor in its molten state, and forms crystals that are hard and brittle. These properties are characteristic of what type of chemical bond?
- AMetallic bond
- BCovalent bond
- CIonic bond
- DHydrogen bond
Show answer & explanationAnswer & explanation
Correct answer: C. Ionic bond
High melting point, electrical conductivity in molten state (due to mobile ions), and hard/brittle crystalline structure are all classic characteristics of compounds formed by ionic bonds.
Why the other options are wrong
- A. Metallic bonds lead to good conductivity in solid state, malleability, and ductility, not brittleness.
- B. Covalent compounds generally have lower melting points and are poor conductors.
- D. Hydrogen bonds are intermolecular forces, much weaker than ionic bonds, and do not lead to these bulk properties.
Ionic Bonding Properties
Ionic bonds form between a metal and a nonmetal through the transfer of electrons, creating oppositely charged ions that are held together by strong electrostatic forces.
- High melting and boiling points.
- Hard and brittle crystalline solids.
- Good electrical conductors when molten or dissolved in water (due to mobile ions).
- Poor electrical conductors in solid state (ions are fixed in lattice).
Memory trick: Bonds dictate behavior: strong, shared, or sea.