10-minute Quiz : Ch9 Structures and properties of substances

Hexagonal boron nitride has a structure similar to graphite. The structure of hexagonal boron nitride is shown below. Which of the following statements concerning hexagonal boron nitride are correct?

(1) It is a covalent compound.

(2) It is insoluble in organic solvents.

(3) It can conduct electricity.

• A. (1) and (2) only
• B. (1) and (3) only
• C. (2) and (3) only
• D. (1), (2) and (3)

Astatine is a Group VII element. Which of the following predictions are correct?

(1) Astatine is a black solid at room temperature and pressure.

(2) The compound of astatine and iodine is soluble in water.

(3) The compound of astatine and silver can conduct electricity in molten state.

• A. (1) and (2) only
• B. (1) and (3) only
• C. (2) and (3) only
• D. (1), (2) and (3)

Metals can be pulled into wires because

• A. metallic bonds are weak.
• B. metals can conduct electricity.
• C. metal ions in metals pack closely together.
• D. layers of metal ions in metals can slide over one another.

When a solid is added to water, it dissolves to give a colourless solution. The resultant solution does not conduct electricity. The solid probably has a

• A. giant metallic structure.
• B. giant covalent structure.
• C. giant ionic structure.
• D. simple molecular structure.

The table below shows the information of four substances. Which of the above substances is an ionic compound?

• A. W

• B. X

• C. Y

• D. Z

Which of the following statements concerning ionic crystals and metals are correct?

(1) The ionic bonds in ionic crystals and metallic bonds in metals are non-directional.

(2) Both ionic crystals and metals conduct electricity at room temperature.

(3) Metals are ductile while ionic crystals are brittle.

• A. (1) and (2) only
• B. (1) and (3) only
• C. (2) and (3) only
• D. (1), (2) and (3)

Graphite can be used as a lubricant because

• A. it contains delocalized electrons in its structure.
• B. it has a low melting point and so it easily turns into a liquid.
• C. the carbon atoms in its structure are held together by strong covalent bonds.
• D. the layers of carbon atoms are held together by weak van der Waals’ forces.

Which of the following diagrams best represents the structure of a sodium chloride crystal? (In the diagrams, a black dot represents a Na⁺ ion and a white dot represents a Cl⁻ ion.)

• A
• B
• C
• D

Which of the following properties of water shows that it consists of molecules?

(1) It turns anhydrous copper(II) sulphate from white to blue.

(2) It is a poor conductor of electricity.

(3) It boils at 100°C.

• A. (1) and (2) only
• B. (1) and (3) only
• C. (2) and (3) only
• D. (1), (2) and (3)

Consider the following statements and choose the best answer:

1st statement

Diamond is an extremely hard substance.

2nd statement

Diamond has a three-dimensional giant network of carbon atoms.

• A. Both statements are true and the 2nd statement is a correct explanation of the 1st statement.
• B. Both statements are true but the 2nd statement is NOT a correct explanation of the 1st statement.
• C. The 1st statement is false but the 2nd statement is true.
• D. Both statements are false.