The number of complexes from the following with no electrons in the t₂ orbital is ______.
TiCl₄,[MnO₄]⁻,[FeO₄]²⁻,[FeCl₄]⁻,[CoCl₄]²⁻

Solution

Chemistry ma’am · 3 steps

All five are tetrahedral, so the e set fills first and t₂ gets electrons only after e holds 2.

1. Tetrahedral splitting. All five species are tetrahedral. In a tetrahedral field the order flips from octahedral: the two e orbitals lie lower and the three t₂ orbitals lie higher. Δₜ is small, so these complexes are high spin.
2. Filling rule. The first two d electrons go into e, one in each orbital. From the third electron on, t₂ starts to fill. So only d⁰, d¹ and d² ions leave t₂ empty.

   Species	Metal ion	d count	Configuration	t₂ empty?
   TiCl₄	Ti⁴⁺	d⁰	e⁰ t₂⁰	yes
   [MnO₄]⁻	Mn⁷⁺	d⁰	e⁰ t₂⁰	yes
   [FeO₄]²⁻	Fe⁶⁺	d²	e² t₂⁰	yes
   [FeCl₄]⁻	Fe³⁺	d⁵	e² t₂³	no
   [CoCl₄]²⁻	Co²⁺	d⁷	e⁴ t₂³	no

3. So. TiCl₄, [MnO₄]⁻ and [FeO₄]²⁻ have no electrons in t₂. The count is 3, option (c).

The idea to keep. In tetrahedral complexes e is the lower set and t₂ the upper one. Find the d count from the oxidation state, then fill e before t₂.

Answer from the NTA final answer key. Solution by PrepWiser.