Thank you for posting your question here at brainly. Below is the solution. I hope the answer will help. 
<span>Cl^- 1s^2 2s^2p^6 3s^2 3p^6 1s^2 2s^2p^6 S = 10; 3s^2 3p^6 S = 0 </span>
<span>Zeff = Z-S = 17- 10 =7 </span>
<span>K^+ 1s^2 2s^2p^6 3s^2 3p^6; 1s^2 2s^2p^6 S = 10; 3s^2 3p^6 S = 0 </span>
<span>Zeff = Z-S = 19- 10 = 9 
</span>
S = 2 + 6.8 + 2.45 = 11.25 
<span>Zeff(Cl^-) = 17 – 11.25 = 5.75 </span>
<span>K^+ 1s^2 2s^2p^6 3s^2 3p^6 same S as for Cl^- but Z increases by 2 hence </span>
<span>Zeff(K^+) = 19 - 11.25 = 7.75</span>
        
                    
             
        
        
        
Answer:
-1m/s
Explanation:
We can calculate the speed of block A after collision 
According to collision theory:
MaVa+MbVb = MaVa+MbVb (after collision)
Substitute the given values 
5(3)+10(0) = 5Va+10(2)
15+0 = 5Va + 20
5Va = 15-20
5Va = -5
Va = -5/5
Va = -1m/s
Hence the velocity of ball A after collision is -1m/s
Note that the velocity of block B is zero before collision since it is stationary 
 
        
             
        
        
        
Answer: Dark matter.
Explanation: Hope it helps :)
 
        
                    
             
        
        
        
You need to post a picture bro