10 REM Periodic table
20 CLS
30 DIM a(7),b(7)
40 GOSUB 100
50 FOR j = 0 TO 9
60  READ anum : GOSUB 140
70 NEXT j
80 END
90 REM Set arrays A, B.
100 FOR i = 0 TO 7 : READ a(i) : NEXT i
110 FOR i = 0 TO 7 : READ b(i) : NEXT i
120 RETURN
130 REM Show row AND column FOR element
140 i = 7
150 WHILE a(i) > anum
160  i = i-1
170 WEND
180 m = anum+b(i)
190 r = INT(m/18)+1
200 c = m MOD 18+1
210 PRINT anum "-> " r c
220 RETURN
230 REM DATA
240 REM Arrays A, B.
250 DATA 1,2,5,13,57,72,89,104
260 DATA -1,15,25,35,72,21,58,7
270 REM Example elements (atomic numbers).
280 DATA 1,2,29,42,57,58,72,89,90,103