Accourding to slater's rule, order of effective nuclear charge for last electron in case of Li,Na and K :-

(1)Li >Na >K

(2)K >Na> Li

(3)Na> Li >K

(4)Li

Answer is optiona (4) plzz explain

Asked by jhajuhi19 | 19th Feb, 2019, 08:01: PM

Expert Answer:

Effective nuclear charge Zeff = Nuclear charge (Z) - Screening constant (S)
 
For Lithium (Li)
 
screening constant is 1.7 
nuclear charge is 3
 
Effective nuclear charge = 3- 1.7
 
                                    =1.3
For Sodium (Na) 
 
screening effect constant is 8.8
nuclear charge is 11
 
Effective nuclear charge = 11 - 8.8 
 
                                    =2.2
 
For Potassium (K)
 
screening effect constant is 16.8
 
Nuclear charge is 19
 
Effective nuclear charge = 19 - 16.8
 
                                    = 2.2
 
Also for Rubidium and Caesium, the effective nuclear charge is 2.2
 
It is observed that in a group the effective nuclear charge remains the same.
 
So the effective nuclear charge for lithium is smaller as compared to sodium and potassium.
 

Answered by Varsha | 20th Feb, 2019, 03:44: PM

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