JEE Advanced 2024 · Paper 1 · Chemistry Q11

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ChemistryInteger+4Question 45 of 51

Among $\ce{V(CO)6}$ , $\ce{Cr(CO)5}$ , $\ce{Cu(CO)3}$ , $\ce{Mn(CO)5}$ , $\ce{Fe(CO)5}$ , $\ce{[Co(CO)3]^3-}$ , $\ce{[Cr(CO)4]^4-}$ , and $\ce{Ir(CO)3}$ , the total number of species isoelectronic with $\ce{Ni(CO)4}$ is _____.

[Given, atomic number: V = 23, Cr = 24, Mn = 25, Fe = 26, Co = 27, Ni = 28, Cu = 29, Ir = 77]

Your answer

Answer and worked solution

Official answer: 3

Here isoelectronic means the same metal valence-electron count as $\ce{Ni(CO)4}$ : $10 + 4\times2 = 18$ . Count metal group electrons + 2 per CO + negative charge:

Species	Count
$\ce{V(CO)6}$	$5 + 12 = 17$
$\ce{Cr(CO)5}$	$6 + 10 = 16$
$\ce{Cu(CO)3}$	$11 + 6 = 17$
$\ce{Mn(CO)5}$	$7 + 10 = 17$
$\ce{Fe(CO)5}$	$8 + 10 = 18$ ✓
$\ce{[Co(CO)3]^3-}$	$9 + 6 + 3 = 18$ ✓
$\ce{[Cr(CO)4]^4-}$	$6 + 8 + 4 = 18$ ✓
$\ce{Ir(CO)3}$	$9 + 6 = 15$

Answer: 3.

Topics:Metal carbonyls and EAN rule

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JEE Advanced 2024 · Paper 1, Chemistry question 11