A-Level Chemistry revision: Atomic Structure and Bonding. Learning objectives, key points, worked examples and practice questions across AQA, Edexcel, OCR, WJEC and CCEA.
๐ Key Points
Key Fact: Atomic structure: pโบ, nโฐ, eโป; isotopes = same Z, different A; electron config: 1s^22s^22pโถ...
Key Fact: Ionisation energy: increases across period (โZ_eff), decreases down group (โshielding, โn)
Key Fact: Ionic: metal + non-metal, electron transfer, lattice; Covalent: non-metal + non-metal, sharing
Describe atomic structure: subatomic particles, isotopes, electron configuration
Explain ionisation energies and trends across periods/down groups
Understand ionic, covalent, metallic, and hydrogen bonding
Use electronegativity to predict bond polarity and type
Describe shapes of molecules using VSEPR theory
Understand intermolecular forces: van der Waals, dipole-dipole, hydrogen bonding
Relate structure and bonding to physical properties (melting point, conductivity, solubility)
๐ก Worked Example
Exam-Style Question
Question: Explain why HโO has a higher boiling point than HโS despite similar molecular mass
Model Answer:
HโO has H-bonding (O is highly electronegative, lone pairs); HโS has only dipole-dipole and London forces. H-bonding is much stronger -> more energy to separate molecules -> higher BP
โ Practice Questions
Questions:
Write electron configuration of Fe^2โบ (Z=26)
Predict shape and bond angle of NHโ, COโ, SFโ