Physical Chemistry #10: Intermolecular Forces, Electronegativity & Bond Polarity (Slides & Tasks)

In this lesson we discuss how intermolecular forces arise due to the concept of electronegativity and bond polarity and other bond properties. This is lesson ten in our physical chemistry series for Unit 3: Chemical Bonding (from the Cambridge International AS Chemistry Curriculum (9701) 2019-2021 curriculum).

LESSON OBJECTIVE: Understand the different intermolecular forces and their implications for a molecules physical properties. Explain these forces in terms of electronegativity and polarity.

Learning Outcomes (from the Cambridge AS Chemistry Curriculum 2019-2021):
3.3 Intermolecular forces, electronegativity and bond properties.
a) describe hydrogen bonding, using ammonia and water as simple examples of molecules containing N-H and O-H groups

b) understand, in simple terms, the concept of electronegativity and apply it to explain the properties of molecules such as bond polarity, the dipole moments of molecules and the behaviour of oxides with water

c) explain in terms of bond energy, bond length and bond polarity and use them to compare the reactivities of covalent bonds

d) describe intermolecular forces (van der Waals’ forces) based on permanent and induced dipoles, as in, for example, CHCl3(l); Br2(l) and the liquid Group 18 element.