The chemical formula for a compound with one barium ion (Ba²⁺) and two chloride ions (Cl⁻) is BaCl₂.

Here's why:

* Barium (Ba): Barium has a +2 charge.

* Chlorine (Cl): Chlorine has a -1 charge.

To balance the charges, you need two chloride ions (2 x -1 = -2) to cancel out the +2 charge of the barium ion.