Yes , it is true.
Some of these metals are: Calcium, Magnesium, Sulfur, Sodium, Potassium, ...
Li (Lithium), Na (Sodium), K (potassium). They are highly reactive - they react violently with water and also react with oxygen.
Yes, and violently so.
Sodium react violently with water releasing hydrogen !
No, but esters do react with some acids.
Potassium reacts faster and violently with acids than sodium.
Sodium and potassium reacting violently with water is a chemical reaction, causing a chemical change.
Magnesium, Calcium and Sodium react violently with acids as compare to Aluminium.
Sodium will react violently with dilute hydrochloric acid.
because sodium is unstable
Some of these metals are: Calcium, Magnesium, Sulfur, Sodium, Potassium, ...
Yes.
Yes, violently.
It reacts rapidly but not violently unless heated.
Coper
Yes, sodium reacts violently with water.
Metallic magnesium reacts violently with acids.