Question

12. Which of the following would have the greatest effective nuclear charge, and what is the Zelf of that species? Mo, Ru, and Mot

Answer 1

Answer Effective Nuclear Charge is the average nuclear Charge felt by individual election in an atom, taking into consideration the shielding effect of inner shell electron. Zef zz-s where 2 = atomic number hd sa shielding or screening constant Screening or shielding Constant can be caloulabed by the slater's rules. onun To calculate the shielding constant for an electron in an np as or ns orbital 1) Write out the electronie configuration of the element in the following order and groupings? (13) (28; 20) (33,3P) (3d) (4540) (ud) (55, 5p efC. 1) Electrons in any group to the right of the (ns, np group contribute nothing to the shielding constant. 3. All of the other electrons in the (ns, up) group shield the valence electron to an extent of 0:35 each. 4. All elections in the ni shell shield to an extent of 0.85 cach.

5. All electrons n-2 or lower shield completely that is their contribution is 1.00 each, when the electrons being shielded is in an nd or nt group;sules 2 and 3 are the same but rules 4 and 5 becomes us 6. All electrons in groups lying to the left of the nd or st group contribute 1.00

Atomie no of mo = 42 Electronie configuration (15) (23, 2018 (35,3098 (34)' °(,409 153'40) Consider the valence (ad) election of in the atom 42 mo S> (4X0°35) + ( 37 X 1'00) 2 38.4 Zeff - 2-5 -(42 - 38.4) - 3.6 Atomic no of mot = 42 Electronic configuration (15) 125,20)% (35, 3p)8 (3d)'0 (48,40 Consider the 4d electron so (4X01357) +(36x 1:00) 23714 Zeff = 2-5=(42 - 3714) = 4.6 Atomic no of Ru = 44 Electronic configuration 110"(25,2) (33,3.5 (34)° (43,403 (59" (40)8 Consßder the hd electron SM (2X0.35) +(36X1'00) 2 38145 Zell-z-s-(44-38-45) = 5155 So among the three Ru has the greatest effective nuclear Charge.