βοΈ Topic 2 Β· Microscopic World I & II
Atomic structure, Periodic Table, Chemical bonds (ionic + metallic) Β· Core DSE Chemistry theme π All 6 batches complete
π Topic 2 Three Themes
- Theme 1 Atomic Structure: Dalton β Thomson β Rutherford β Bohr β Electron cloud; Isotopes; Relative Atomic Mass; Electronic arrangement
- Theme 2 Periodic Table: Group I/II/VII/0 properties; Electronic arrangement and position; Reactivity trends
- Theme 3 Chemical Bonds: Ionic bond + giant lattice; Metallic bond + delocalised electrons; Chemical formula writing and naming
π Batch 1 Β· Atomic Structure
p01-p08. Atomic structure evolution (Dalton β electron cloud), protons/neutrons/electrons, relative mass, Β³β΅ββCl example.
π Batch 2 Β· Isotopes & Electronic Arrangement π New
p09-p15. Isotopes (same chemistry, different physics), weighted average relative atomic mass, electron shells (2nΒ²), first 20 elements quick reference.
π Batch 3 Β· Periodic Table & Group I/II π New
p16-p23. Periodic Table structure (Period = shell number, Group = outermost shell electrons), Group I alkali metals, Group II alkaline earth metals reactivity trends.
π Batch 4 Β· Halogens, Noble Gases & Ions π New
p24-p31. Group VII halogens (reactivity decreases down group), Group 0 noble gases (octet rule), ion formation, octet rule, Periodic Table history.
π Batch 5 Β· Ionic Bond, Chemical Formula & Naming π New
p32-p39. Ionic bond formation (electron transfer), giant lattice, 4-step chemical formula writing, polyatomic ions, naming rules, ion colours and migration.
π Batch 6 Β· Metallic Bond & Topic 2 Summary π New
p40-p44. Metallic bond model (delocalised electron sea), 4-step chemical formula writing, Topic 2 three themes complete summary, mastery checklist.
π― Topic 2 Complete Core (Must Memorise)
- Atom = proton + neutron + electron; Z = proton number; A = Z + neutron number
- Electronic arrangement: shell K=2, L=8, M=18 (formula 2nΒ²)
- Periodic Table: Period = shell number; Group = outermost shell electron number
- Group I, II reactivity increases down the group; Group VII reactivity decreases down the group
- Octet rule: Atoms tend to acquire 8 outermost shell electrons (He = 2)
- Ionic bond: Metal loses electrons + non-metal gains electrons β electrostatic attraction β giant lattice
- Metallic bond: Cation + delocalised electron sea β explains conductivity, malleability, high melting point
- Chemical formula: cation left, anion right; cross charges; simplify ratio; brackets for polyatomic ions
- Ion naming: -ide (monatomic anion), -ate/-ite (oxoanion), Roman numerals for multivalent metals