Properties of covalent substances | Exit Quiz | Oak National Academy

What is the typical size of atomic radii and bond lengths?

• 10⁻⁶ m

• 10⁻⁸ m

• 10⁻¹⁰ m

• 10⁻¹ ²m

Answer explanation

The typical size of atomic radii and bond lengths is in the order of 10⁻¹⁰ m, which is very small.

Why can't simple covalent substances conduct electricity?

• They have no atoms.

• They have no free moving electrons.

• They have no electrons.

• They are too small.

• They have no free moving ions.

Answer explanation

Simple covalent substances cannot conduct electricity because they have no free moving charge carriers.

Giant covalent structures have high melting and boiling points because strong ___ need to be broken, which requires a lot of energy.

Answer explanation

Giant covalent structures have high melting and boiling points because strong covalent bonds need to be broken, which requires a lot of energy.

What are intermolecular forces?

• Strong forces between atoms.

• Forces of attraction between molecules.

• Forces that hold nuclei together.

• Forces that repel electrons.

Answer explanation

Intermolecular forces are weak forces of attraction between molecules, which affect the properties of molecular substances.

Which of the following are true of polymers?

• Most polymers exist in the arrangement of the solid state at room temperature.

• Some polymers are made up of smaller molecules called monomers.

• They have a simple covalent structure (molecules).

• They conduct electricity well.

• They are held together by covalent bonds.

Answer explanation

A polymer is a long chain molecule formed by joining small molecules (monomers) together by covalent bonds.

What happens during a change of state in simple covalent substances?

• Covalent bonds are broken.

• Intermolecular forces are overcome.

• Atoms are rearranged.

• Molecules move farther apart.

Answer explanation

During a change of state in simple covalent substances, the intermolecular forces are overcome, but the covalent bonds within the molecules remain intact.