Compounds: oxides, hydroxides, halides, carbonates
s-Block Elements · Chemistry
Study notes
Why does Li₂CO₃ decompose on heating but Na₂CO₃ doesn't? Step 1: Small Li⁺ strongly polarises the large CO₃²⁻ ion (Fajan's rules!). Step 2: Polarisation weakens C–O bonds, favouring CO₂ loss: Li₂CO₃ → Li₂O + CO₂. Step 3: Larger Na⁺ polarises weakly → Na₂CO₃ stable to melting. Step 4: Same reason MgCO₃ decomposes but K₂CO₃ doesn't — size matters!