The symbols of some of the ions are given below
Na+, Mg2+, H+, Cl–, S2–
Using this information, find out the formulae of
(i) sodium carbonate
(ii) magnesium chloride
(iii) hydrogen sulphide
(i) Sodium carbonate
By applying criss-cross method:
Formula: Na2CO3
Thus, the formula for sodium carbonate is Na2CO3.
(ii) Magnesium chloride
By applying criss-cross method:
Formula: MgCl2
Thus, the formula for magnesium chloride is MgCl2.
(iii) Hydrogen sulphide
By applying criss-cross method:
Formula: H2S
Thus, the formula for hydrogen sulphide is H2S.