The number of d-electrons in Fe2+ (atomic number = 26) is not equal to which of the following?
Answer & explanation
Correct answer: option 3
26Fe : [Ar]4s23d6 ; Fe2+ : [Ar]3d6
10Ne : 1s22s22p6
11Na : 1s22s22p63s1 ; Na+ : 1s22s22p6
12Mg : 1s22s22p63s2
17Cl : 1s22s22p63s23p5 ; Cl- : 1s22s22p63s23p6
s-electrons in Mg is not equal to that of d-electrons in Fe2+.