n the reaction will be Exothermic, where heat will be released. .
 
        
             
        
        
        
Answer:
Waves involve the transport of energy without the transport of matter. In conclusion, a wave can be described as a disturbance that travels through a medium, transporting energy from one location (its source) to another location without transporting matter.
Explanation:
hope this helps, I tried to give an easy definition  :)
 
        
             
        
        
        
Heat is needed to change solid to liquid even to gas!
        
                    
             
        
        
        
Answer:
Henry Moseley
Explanation:
Dmitry Mendeleef and Lothar Meyer proposed a periodic table based on the atomic mass. 
They stated a periodic law expressed as "chemical properties of elements are a periodic function of their atomic weights". 
But, Henry Moseley in 1900s re-stated periodic law by changing the basis of the law from atomic weight to atomic number. 
The present periodic law is stated as "the properties of elements are a periodic function of their atomic number". 
 
        
             
        
        
        
Explanation:
 Calcium is the element that has 2 valence electrons.