Classification Of Elements And Periodicity In Properties Ques 303
Question: The atomic numbers of vanadium (V), chromium (Cr), manganese (Mn) and iron (Fe) are, respectively 23, 24, 25 and 26. Which one of these may be expected to have the highest second ionisation enthalpy-
Options:
A) V
B) Cr
C) Mn
D) Fe
Show Answer
Answer:
Correct Answer: B
Solution:
[b] $ F{{e}^{+}}(26)=[Ar]3d^{6},4s^{1} $
$ M{{n}^{+}}\text{(}25\text{)}=[Ar]3d^{5}4s^{1} $
$ {{V}^{+}}\text{(}23\text{)}=[Ar]3d^{2}4s^{2} $
$ C{{r}^{+}}\text{(}24\text{)}=[Ar]3d^{5}4s^{0} $
(By first IP) The electronic configuration of $ C{{r}^{+}} $ is most stable, hence formation of $ C{{r}^{2+}} $ by second IP requires maximum enthalpy.
