There are 12<span> protons and </span>10<span> electrons in a </span><span>Mg<span>2+</span></span><span> ion, the normal amount of neutrons is </span>12<span>.</span>
        
             
        
        
        
Density is a physical property. It's measured and doesn't change the object chemically.
        
             
        
        
        
Answer:
D) He did not multiply the chlorine and oxygen atoms by the coefficient 4.
Explanation:
The coefficient 4 at the beginning of the chemical formula indicates that there are four Ca(ClO3)2 molecules. Think of this as Ca(ClO3)2 × 4. This means that he had to multiply the number of atoms for each element by 4 as well, so he should've ended up with 4 total calcium atoms (which is correct), 8 total chlorine atoms, and and 24 total oxygen atoms. He did not get all these answers because he didn't multiply the chlorine and oxygen atoms by the coefficient 4. 
 
        
                    
             
        
        
        
Answer:
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Explanation:
 
        
                    
             
        
        
        
Answer:
Mass =  99.8 g  
Explanation:
Given data:
Mass of potassium nitride = ?
Mass of nitrogen produced = 10.65 g
Solution:
Chemical equation:
2K₃N→ 6K + N₂ 
Moles of nitrogen:
Number of moles = mass/ molar mass
Number of moles =  10.65 g / 28 g/mol
Number of moles = 0.38 mol
Now we will compare the moles of nitrogen with potassium nitride.
                         N₂              ;         K₃N
                          1               :            2
                          0.38          :          2×0.38 =0.76
Mass of potassium nitride:
Mass = molar mass × number of moles 
Mass =    131.3 g/mol ×   0.76 mol
Mass =  99.8 g