Answer:NH4F ( ammonium fluoride)
Explanation:
NH4 is a cation with a positive 1 charge and F an anion having negative 1 oxidation number. Do the criss-cross rule for both cations and anions. So the charge of NH4 which is +1 will be the subscript of F and the charge of F which is -1 will be the subscript of NH4. Both have the same numerical value of 1 so we can cancel them out in the final equation of the chemical compound.