the formation of cations by using electron dot structures are :
a) Al 
  .
Al .    losing the three valence electrons makes the Al³⁺
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b) Sr :   
   Sr :   losing the two valence electrons makes Sr²⁺
c) Ba
  : Ba , losing the two valence electrons makes it Ba²⁺
A Lewis electron dot diagram is a representation of the valence electrons of an atom that employments specks around the image of the element. The number of dots equals the number of valence electrons within the molecule. These dots are arranged to the right and left and over and underneath the symbol, with no more than two dots on a side. Cations are the positive ions shaped by the loss of one or more electrons. The foremost commonly shaped cations of the representative elements are those that include the loss of all of the valence electrons.
To know more about the lewis electron dot diagram refer to the link brainly.com/question/14191114?referrer=searchResults.
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A chemical equation is a short hand expression of a chemical reaction. There aretwo<span> parts to a chemical equation. The reactants are the elements or compounds on the left side of the arrow (-->). The elements and compounds to the right of the arrow are the products.</span>
        
             
        
        
        
 <span>This question asksyou to apply Hess's law. 
You have to look for how to add up all the reaction so that you get the net equation as the combustion for benzene. The net reaction should look something like C6H6(l)+ O2 (g)-->CO2(g) +H2O(l). So, you need to add up the reaction in a way so that you can cancel H2 and C. 
multiply 2 H2(g) + O2 (g) --> 2H2O(l) delta H= -572 kJ by 3 
multiply C(s) + O2(g) --> CO2(g) delta H= -394 kJ by 12 
multiply 6C(s) + 3 H2(g) --> C6H6(l) delta H= +49 kJ by 2 after reversing the equation. 
Then, 
6 H2(g) + 3O2 (g) --> 6H2O(l) delta H= -1716 kJ 
12C(s) + 12O2(g) --> 12CO2(g) delta H= -4728 kJ 
2C6H6(l) --> 12 C(s) + 6 H2(g) delta H= - 98 kJ 
______________________________________... 
2C6H6(l) + 16O2 (g)-->12CO2(g) + 6H2O(l) delta H= - 6542 kJ 
I hope this helps and my answer is right.</span>
        
                    
             
        
        
        
Answer:
the HOMO-LUMO energy difference in ethylene is greater than that of cis,trans−1,3−cyclooctadiene
Explanation:
The λmax is the wavelength of maximum absorption. We could use it to calculate the HOMO-LUMO energy difference as follows:
For ethylene
E= hc/λ= 6.63×10^-34×3×10^8/170×10^-9= 1.17×10^-18J
For cis,trans−1,3−cyclooctadiene
E= hc/λ=6.63×10^-34×3×10^8/230×10^-9=8.6×10^-19J
Therefore, the HOMO-LUMO energy difference in ethylene is greater than that of cis,trans−1,3−cyclooctadiene 
 
        
             
        
        
        
Answer:
wheres the question??????