Answer:
Both gives hydroxides, but
Calcium reacts with water to give calcium hydroxide Ca(OH)2. this product is slightly soluble in water.
Aluminium is less reactive than Ca, so it reacts with only steam, to give aluminium hydroxide Al(OH)3. This product is insoluble in water.
Because at atmospheric pressure the boiling point is below room temperature, just like Oxygen, Nitrogen etc
Metalloids are elements that have both metal and nonmetal properties