Alkali Metals (Group 1) elements experience an increase in the vigour of their reaction in water as they go down the group (as the atomic number increase). As such the most reactive Alkali Metal would be
 FRANCIUM, which is at the base of Group One.
Quite frankly, you do not want Francium to react with water- that's a huge explosion on your hand.
 
        
        
        
Answer:
Everything is composed of atoms! which are the indivisible building blocks of matter and cannot be destroyed. All atoms of an element are identical. The atoms of different elements vary in size and mass.
Explanation:
Hope this helped
 
        
                    
             
        
        
        
Answer: The element Na (Sodium) is getting oxidized and Hydrogen is getting reduced.
Explanation: 
Oxidation reactions are the reactions in which addition of oxygen takes place.
Reduction reactions are the reactions in which loss of oxygen takes place.
For a given reaction:

Sodium is getting oxidized because there is an addition of reaction with that element.
Hydrogen is getting reduced because there is a removal of oxygen with that element.