Answer:
I would say element
Explanation:
because it is made of two different types of atoms chemically bonded together!
I'm sorry if wrong! 
 
        
             
        
        
        
The balanced equation for the reaction between KOH and HBr is as follows;
KOH + HBr --> KBr + H₂O
stoichiometry of KOH to HBr is 1:1
number of KOH moles reacted - 0.25 mol/L x 0.015 L = 0.00375 mol
according to molar ration 
number of KOH moles reacted = number of HBr moles reacted 
number of HBr moles reacted - 0.00375 mol 
if 12 mL of HBr contains - 0.00375 mol 
then 1000 mL of HBr contains - 0.00375 mol / 12 mL x 1000 mL = 0.313 mol
therefore molarity of HBr is 0.313 M
        
             
        
        
        
Explanation:
Supposing we have to find the difference between the number of electrons in Selenium and Aluminium. 
Well, electrons can be transformed to an atomic number, so if SE is 34, that means it has 34 electrons. AI has an atomic number of 13, which means it has 13 electrons. So the difference is that more electrons than AI are available from SE.
 
        
             
        
        
        
Definitely gonna be the 3rd one is your answer
        
                    
             
        
        
        
An intensive property does not change when you take change when you take away some of the sample the producers that a student could use to examine the intensive property of a rectangular block of wood