Q44 / 180 · AIIMS 2004 · Chemistry

Assertion : The free gaseous $\mathrm{Cr}$ atom has six unpaired electrons. Reason : Half-filled $s$ orbital has greater stability.

  • A
    If both assertion and reason are true and reason is the correct explanation of assertion
  • B
    If both assertion and reason are true but reason is not the correct explanation of assertion
  • Correct answer
    C
    If assertion is true but reason is false
  • D
    If both assertion and reason are false.

Solution

$:{ }_{24} \mathrm{Cr} \rightarrow[\mathrm{Ar}] 3 d^4 4 s^2$ $\mathrm{Cr} \rightarrow[\mathrm{Ar}] 3 d^5 4 s^1$ Half-filled $d$-orbital has greater stability.

Hence, the correct answer is option: 'C'.

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