The general formula of a perchlorate is MeClO4, where Me is a metal. The anion perchlorate is monovalent.
ClO3-
KClO4
The silver ion is Ag+ and the perchlorate ion is ClO4-, so silver perchlorate would have the formula of AgClO4.
Formula: ClO4-
ClO4-
ClO4-
ClO4-
Formula: NH4ClO4
The formula is ClO4-
NH4ClO4
AgClO4
KClO4
Formula: Fe(ClO4)2
Formula = Y(ClO4)3