Here's how to determine the number of unpaired electrons in the Tl ion:

1. Electronic Configuration of Thallium (Tl)

* Thallium has an atomic number of 81.

* Its electronic configuration is: [Xe] 4f¹⁴ 5d¹⁰ 6s² 6p¹

2. Ionization of Thallium

* Thallium typically forms a +1 ion (Tl⁺). This means it loses one electron.

3. Electronic Configuration of Tl⁺

* The electron lost will be from the 6p¹ orbital.

* The electronic configuration of Tl⁺ becomes: [Xe] 4f¹⁴ 5d¹⁰ 6s²

4. Unpaired Electrons

* All the orbitals in the electronic configuration of Tl⁺ are completely filled.

* This means there are no unpaired electrons in the Tl⁺ ion.

Therefore, the Tl⁺ ion has 0 unpaired electrons.