Beautiful Bonds The World of Covalent and Metallic Solids

The video tutorial explains different types of solids: ionic, molecular, covalent, and metallic. Ionic solids consist of cations and anions held by ionic bonds, acting as insulators in solid form but conductors when molten or in solution. Molecular solids are categorized into non-polar, polar, and hydrogen-bonded, with varying intermolecular forces affecting their properties. Covalent solids, like diamond and graphite, have strong covalent bonds, with graphite being a good conductor due to free electrons. Metallic solids feature a sea of electrons around metal ions, making them good conductors and malleable.

What is a key characteristic of ionic solids in their solid state?

• They act as insulators.

• They are malleable.

• They are good conductors of electricity.

• They have low melting points.

Which type of molecular solid is held together by weak van der Waals forces?

• Ionic solids

• Hydrogen-bonded molecular solids

• Non-polar molecular solids

• Polar molecular solids

What type of bond holds the molecules together in hydrogen-bonded molecular solids?

• Ionic bonds

• Covalent bonds

• Hydrogen bonds

• Metallic bonds

Which of the following is a property of covalent network solids?

• They are soft and flexible.

• They have low melting points.

• They are hard and brittle.

• They are good conductors of electricity.

What is the hybridization of carbon atoms in diamond?

• sp2

• sp3d

• sp3

• sp

Why does graphite act as a lubricant?

• It is malleable.

• It is a good conductor of electricity.

• Its layers slide over each other easily.

• It has a high melting point.

What is a defining feature of metallic solids?

• They have low melting points.

• They are poor conductors of electricity.

• They are brittle.

• They consist of a sea of electrons.