B.) Valence Electrons. The nucleus of the valence electrons attracts and pulls atoms together.
        
                    
             
        
        
        
 Answer:
1, just I) color.
Explanation:
Physical properties are the properties that can be observed without changing the composition of a substance, such as color, temperature, density, and boiling point. 
 
A physical change is a change in the substance that only modifies its aggregation state, such as solidification, and boiling. 
 
Chemical properties are the properties that need a reaction to being observed, such as the combustibility, which needs a combustion reaction to being quantified. 
When a chemical reaction occurs, and the composition of the substance change, it's a chemical change.
 
So, the heating copper with carbon is a chemical reaction, and purification by electrolysis is too. Color is the only physical property.
 
        
             
        
        
        
Answer:

Explanation:
Hello!
In this case, since the decomposition of sodium hydrogen carbonate is:

Thus, since there is a 2:1 mole ratio between the sodium hydrogen carbonate and sodium carbonate, and the molar masses are 84.01 and 105.99 g/mol respectively, we obtain the following theoretical yield:

Best regards!
 
        
             
        
        
        
Simply look at the periodic table and fill in what you know based on the table 
The number of protons = atomic number 
The number of electrons, Which is the same as the atomic number for atoms. 
The number of valence electrons that is given by the group that the element is in, the top number of each column in the periodic table. 
        
             
        
        
        
Omg hard question but it’s also amazing imma think about that question