The alkali metal cations then accept {HEAD ~ electrons} from {TAIL ~ electrode} 18 and return to their elemental state 
from
The alkali metal cations then accept { HEAD ~ electrons } from { TAIL ~ electrode } 18 and return to their elemental state
OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD REL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH