How bonding and structure are related to the properties of substances common mistakes

Common mistakes

• Misunderstanding Ionic Conductivity

  Students often think that ionic compounds conduct electricity in their solid state.

  Fix itExplain that ionic compounds only conduct electricity when they are molten or dissolved in water, as this is when ions are free to move.

• State of Small Molecular Substances

  Students often state that small molecular substances are always gases at room temperature.

  Fix itEmphasize that small molecular substances are usually gases or liquids at room temperature, not exclusively gases.

• Properties of small molecules correction for Misunderstanding Melting

  Students often think that small molecular substances have low melting and boiling points because the covalent bonds within the molecules are weak This error matters in Properties of small molecules because it drifts away from the objective: Explain why small molecular substances often have low melting points and low boiling points.

  Fix itCorrect it by naming the exact chemistry idea, using precise bonding or structure vocabulary, and linking the answer back to Properties of small molecules. For this objective, students should explain why small molecular substances often have low melting points and low boiling points.

• Confusing Intermolecular Forces with Covalent Bonds

  Students often state that covalent bonds are broken when small molecular substances melt or boil.

  Fix itStudents should clarify that it is the weak intermolecular forces that are overcome during melting or boiling, not the covalent bonds within the molecules.

• Covalent Bonds Misunderstanding

  Students often think that covalent bonds are broken when small molecular substances melt or boil.

  Fix itStudents should understand that during melting or boiling, it is the weak intermolecular forces that are overcome, not the covalent bonds within the molecules.

• Confusing Size with Properties

  Students often think that larger molecules always have higher melting and boiling points without considering the type of intermolecular forces present.

  Fix itEmphasize that while larger molecules may have higher melting and boiling points, it is also important to consider the strength of intermolecular forces, which can vary.

• Misunderstanding Conductivity

  Students often think that small molecular substances can conduct electricity because they contain atoms that are bonded covalently.

  Fix itEmphasize that small molecular substances usually do not conduct electricity because they lack free-moving charged particles, unlike ionic compounds.

• Confusing Intermolecular Forces with Covalent Bonds

  Students often state that covalent bonds are broken when small molecular substances melt or boil.

  Fix itStudents should clarify that it is the weak intermolecular forces that are overcome during melting or boiling, not the covalent bonds within the molecules.

• Misunderstanding Polymer Structure

  Students often describe polymers as small molecules instead of very large molecules.

  Fix itEmphasize that polymers are characterized by their large size and are made from many atoms linked by covalent bonds.

• Misidentifying Polymers

  Students often confuse polymers with small molecules, failing to recognize the size and structure differences in diagrams.

  Fix itFocus on identifying the repeating units and the large size of polymers in diagrams, and compare them to the simpler structures of small molecules.