The correct formula : BeSO₄
Further explanation
Chemical formula shows the composition number of the constituent atoms
Polyatomic ion consists of 2 or more ions
The equal charge of the two ions will cancel each other out, while the different charges of the two ions will be crossed each other
Be²⁺ (monatomic ion) has a positive charge of +2, while SO₄²⁻ (polyatomic ion) has a negative -2 charge, so that the two charges with the same magnitude but with different charges cancel each other out so that the compound form is BeSO4
