The predicted general formula for a compound formed between an alkali metal (Group 1) and sulfur is M₂S, where M represents the alkali metal.

Here's why:

* Alkali metals have a +1 charge when they form ions (M⁺).

* Sulfur has a -2 charge when it forms ions (S⁻²).

* To achieve a neutral compound, you need two alkali metal ions (2 x +1 = +2) to balance the charge of one sulfur ion (-2).

Therefore, the general formula for these compounds is M₂S.

Examples:

* Lithium sulfide: Li₂S

* Sodium sulfide: Na₂S

* Potassium sulfide: K₂S

* Rubidium sulfide: Rb₂S

* Cesium sulfide: Cs₂S