Do you need to expand one of your Ionic Bond Disc Model sets with some extra ions from the nonmetal ions (F⁻, Cl⁻, Br⁻, I⁻, H⁻, O²⁻, S²⁻, Se²⁻, N³⁻, P³⁻)?

Or, did some of your pieces disappear? The Nonmetal Ion Set will get you back up to speed inexpensively.