metal oxide

Is all metal oxide ( except those of group 1 ) insoluble in water?

The oxides of all Group I metals react with water to give soluble metal hydroxides.
Li2O(s) + H2O(l) → 2Li(OH)2(aq)
Na2O(s) + H2O(l) → 2Na(OH)2(aq)
K2O(s) + H2O(l) → 2K(OH)2(aq)
Rb2O(s) + H2O(l) → 2Rb(OH)2(aq)
Cs2O(s) + H2O(l) → 2Cs(OH)2(aq)

The oxides of some Group II metals (Ca, Sr and Ba)react with water to give soluble metal hydroxides, but the solubility of the metal hydroxides are not high.
CaO(s) + H2O(l) → Ca(OH)2(s)
SrO(s) + H2O(l) → Sr(OH)2(s)
BaO(s) + H2O(l) → Ba(OH)2(s)

The oxides of metals in other groups are insoluble in water.

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when aluminium oxide is added to excess sodium hydroxide, what will be formed?

Alumnium oxide is an amphoteric oxide, which dissolves in both dilute strong acids and dilute strong alkalis. Metal oxide dissolves in excess sodium hydroxide solution to form a colourless solution of sodium aluminate.
Al2O3(s) + 3H2O(l) + 2NaOH(aq) → 2Na[Al(OH)4](aq)
or Al2O3(s) + 3H2O(l) + 2OH-(aq) → 2[Al(OH)4]-(aq)

Is all metal oxide ( except those of group 1 ) insoluble in water?
Wrong~只有KO,NaO or more reactive metal才會生成soluble in water的metal oxide~~其他無K同Na咁reactive的,都是insoluble in water的metal oxide~
when aluminium oxide is added to excess sodium hydroxide, what will be formed?
係無O野form,佢在EXCESS的NaOH中,會Soluble and it is colourless~
但當佢在少量的NaOH中時,就會變成white precipitate~~