International Baccalaureate IB Chemistry

Deduce the Lewis formula of molecules and ions for up to four electron pairs on each atom.

Lewis formulas show all the valence electrons (bonding and non‑bonding pairs) in a covalently bonded species. 

Molecules containing atoms with fewer than an octet of electrons should be covered. Organic and inorganic examples should be used.

Explain the relationship between the number of bonds, bond length and bond strength.

Predict the electron domain geometry and the molecular geometry for species with up to four electron domains.

Deduce the polar nature of a covalent bond from electronegativity values.

Deduce the net dipole moment of a molecule or ion by considering bond polarity and molecular geometry.

Describe the structures and explain the properties of silicon, silicon dioxide and carbon’s allotropes: diamond, graphite, fullerenes and graphene.

Deduce the types of intermolecular force present from the structural features of covalent molecules.

The term “van der Waals forces” should be used as an inclusive term to include dipole–dipole, dipole‑induced dipole, and London (dispersion) forces. 

Hydrogen bonds occur when hydrogen, being covalently bonded to an electronegative atom, has an attractive interaction on a neighbouring electronegative atom.

Explain the physical properties of covalent substances to include volatility, electrical conductivity and solubility in terms of their structure.

Explain, calculate and interpret the retardation factor values, R_F.

Deduce resonance structures of molecules and ions.

Discuss the structure of benzene from physical and chemical evidence.

Visually represent Lewis formulas for species with five and six electron domains around the central atom.

Deduce the electron domain geometry and the molecular geometry for these species using the VSEPR model.

Apply formal charge to determine a preferred Lewis formula from different Lewis formulas for a species.

Deduce the presence of sigma bonds and pi bonds in molecules and ions.

Hybridization is the concept of mixing atomic orbitals to form new hybrid orbitals for bonding.

Analyse the hybridization and bond formation in molecules and ions. Identify the relationships between Lewis formulas, electron domains, molecular geometry and type of hybridization. 

Predict the geometry around an atom from its hybridization, and vice versa. 

Include both organic and inorganic examples. Only $sp$, $sp^2$ and $sp^3$ hybridization need to be covered.