Final answer:
The simplest formula for Sr4S4 is SrS, obtained by reducing the subscripts to their simplest ratio of 1:1.
Step-by-step explanation:
The simplest formula for Sr4S4 is found by reducing the subscripts to their lowest whole number ratio. In this case, both the strontium (Sr) and the sulfur (S) have a subscript of 4. Thus, by dividing both subscripts by 4, we obtain the simplest whole number ratio, which is 1:1. Consequently, the simplest formula for Sr4S4 is SrS.