question_answer

Considering \[{{H}_{2}}O\] as a weak field ligand, the number of unpaired electrons in \[{{[Mn{{({{H}_{2}}O)}_{6}}]}^{2+}}\] will be (At. No. of Mn = 25) asas a ajkk [CBSE PMT 2004]

A) Two

B) Four

C) Three

D) Five

Correct Answer: D

Solution :

  \[M{{n}^{25}}\xrightarrow{{}}3{{d}^{5}}+4{{s}^{2}}\] \[M{{n}^{2+}}\xrightarrow{{}}3{{d}^{5}}\] In presence of weak ligand field, there will be no pairing of electrons. So it will form a high spin complex. i.e. the number of unpaired electrons = 5.