Final answer:
Titanium (Ti) has 2 unpaired electrons in its neutral state. Transition metal complexes can have six unpaired electrons if they are in high-spin configurations like [CoF6]3- which has four unpaired electrons. Be2 2- ion is diamagnetic with no unpaired electrons.
Step-by-step explanation:
The electron configuration of a neutral titanium atom (Ti) is [Ar]4s23d2. This means it has 2 electrons in the 4s orbital and 2 electrons in the 3d orbital. Since the 3d orbital can hold up to 10 electrons, and in this case, there are only 2 electrons in the 3d orbitals, they are not paired. This indicates that Ti has 2 unpaired electrons.
Now, considering a complex of a metal in the transition series with six unpaired electrons, this is indeed possible if the metal has a d4, d5, d6 (high spin), or d7 (high spin) configuration where all the electrons occupy separate orbitals according to Hund's rule, which states that electrons will fill an empty orbital before they pair up.
To further illustrate this, we can take the example of [CoF6]3- (high spin) complex. Cobalt has an electron configuration of [Ar]4s23d7. When it becomes Co3+ (as in the complex), it loses the two 4s electrons and one 3d electron, giving it a configuration of [Ar]3d6. In a high-spin complex, the electrons will occupy all available orbitals singly before pairing up due to weak field ligands like F- causing a small crystal field splitting. This would result in four unpaired electrons for the high-spin Co3+ ion in [CoF6]3-.
Furthermore, when considering ions like Be22-, which has two beryllium atoms, since each Be atom has 2 electrons in its 2s orbital, and when they bond, the electrons pair up fully, resulting in no unpaired electrons. Therefore, Be22- is diamagnetic.