Step 1:
Calculate the ionic charges on both atoms:
As Strontium belongs to Group-II in periodic table so it will tend to loose two electrons and form Sr⁺² , i.e.
Sr → Sr⁺² + 2 e⁻
While, Se belonging to Group-VI will tend to gain two electrons and form Se⁻², i.e.
Se + 2 e⁻ → Se⁻²
Step 2:
Multiply the coefficient of each element by the charge of other element.
Se⁻² × 2 = 2 Se⁻² ∴ where 2 is charge on Sr
And,
Sr⁺² × 2 = 2 Sr⁺² ∴ where 2 is charge on Se
So, the formula comes out to be,
Sr₂Se₂
Or divide both coefficients by 2 to have a simplest form. i.e...
SrSe
Result:
One One atoms of each element are needed to create an ionic compound of Strontium Selenide.
