Which is not correctly matched?
(1) Basic strength of oxides:
Cs2O<Rb2O<K2O<Na2O<Li2O
(2) Stability of carbonates:
Na2CO3<K2CO3<Rb2CO3<Cs2CO3
(3) Stability of bicarbonates:
LiHCO3<NaHCO3<KHCO3<RbHCO3<CsHCO3
(4) Melting point:
NaF<NaCl<NaBr<NaI