A partial toy band keeps both filled and empty slots visible. Exact arithmetic here means exact results for the stated model inputs; measured inputs still carry uncertainty and significant-figure limits.

highlighted = computed this step

A partial band has some filled slots

Five electrons fill 5 of the 8 slots.

filled=electrons=5,slots=8filled=electrons=5,\quad slots=8
Partial occupancyThe filled count equals the electron count.sites=4statesPerSite=2electrons=5slots=8filled=5empty=3occupancy=partial

The empty count closes the ledger

The remaining empty count is 3, so the occupancy verdict is partial.

empty=85=3,occupancy=partialempty=8 - 5=3,\quad occupancy=\mathrm{partial}
Partial ledgerThis is occupancy bookkeeping, not a transport law.sites=4statesPerSite=2electrons=5slots=8filled=5empty=3occupancy=partial