Answer: K and Na
Explanation:
Potassium and Sodium have a chemical symbol of K and Na respectively. 
They have similar chemical properties because both
- have only one valence electron,
- form univalent positive ion when they donate their lone outermost electron as shown below
Na --> Na+ + e-
K --> K+ + e-
- are good reducing agents
- react with cold water vigorously to liberate hydrogen gas and form alkalis, so they are known as alkali metals.
- K and Na are placed in Group 1 of the periodic table. 
Thus, unlike the other pairs given, K and Na, have the most similar chemical properties
 
        
             
        
        
        
<span> A homogeneous mixture is composed of a single visible phase while a heterogeneous mixture has two or more</span>
        
             
        
        
        
The postmortem cooling or algor mortis gets fixed by 8- 10 hours after death. The temperature of the body after death can be used to determine the time since death.
        
             
        
        
        
Answer: 5
Explanation: add up all the electrons and it will amount to 23. Arranging by the old model for electronic configuration, we have : 2, 8, 8, 5 
The last number being 5 represent its valence electron 
 
        
                    
             
        
        
        
Hello There!
A Heat Pack is An Example Of A Endothermic Process.
An Endothermic Reaction Is A Reaction That Requires Energy To Move Forward.