The charge ("charge") and selected ("selected") attributes determine valence electron count (see: Electron Counting). Charge refers to formal charge, or the difference between the valence electron count of the element and the sum of bonding and nonbonding electrons of the bound atom. By default, an atom is assigned a charge of zero. Minimum and maximum values for charge are -9 and +9, respectively. The selected attribute adjusts an atom's selection status. Selecting an atom allows it to participate in extended bonding (see: Delocalization Subgraph).