This morning I walked into my Chemistry teacher's office to ask him a question and felt my foot collide with something. I looked down at the floor and saw a load of Periodic Table element flashcards scattered about on the carpet. Presuming I'd walked into a stack of them I hurriedly bent down to pick them up.

"No, don't!" shouted my teacher, rounding the corner. "Let me just check..."

He peered down at the flashcards, his eyes jumping from one to the next to the next... Then he breathed an obvious sigh of relief.

"It's okay," he said. "You've kicked just one out of position. And thankfully you've only picked one of them up. I'll show you where it goes and what I was doing..."

TASK: Which flashcard has been moved out of position, and which other flashcard (not pictured) am I holding in my hand? Where should they both be placed in relation to the other cards on the floor, and why?

Current flashcard arrangement

  • 3
    $\begingroup$ I have to thank you Stiv. When I went to school, half of the elements with atomic number greater than 103 hadn't been created yet, and the other ones had two names due to the Transfermium wars. Thanks to your excellent puzzles, I've got all these new-fangled elements in my memory banks now. $\endgroup$ Commented Sep 23, 2021 at 21:57

1 Answer 1


The cards are laid out:

based on the positioning of the US states whose postal abbreviations they form:


The moved flashcard is:

FL = flerovium = Florida. It should be placed south of Georgia, but is instead placed in Virginia. Knowing Stiv, I feel like there's an Easter egg in here somewhere :-)

The card in your hand is:

CA = calcium = California


The only state whose postal abbreviation is also the atomic symbol of an element but does not appear on the tile is California. It should be placed to the west of CO.

  • 1
    $\begingroup$ Dang, just beat me to it! $\endgroup$
    – hexomino
    Commented Sep 23, 2021 at 21:43
  • 4
    $\begingroup$ @hexomino Can't tell you how fast I was typing :-) $\endgroup$ Commented Sep 23, 2021 at 21:44
  • 1
    $\begingroup$ :D I know the feeling, well done! $\endgroup$
    – hexomino
    Commented Sep 23, 2021 at 21:45
  • 1
    $\begingroup$ Wow, you were lightning fast! This is of course correct - well done :) No Easter Eggs this time actually - not deliberately, at least. If anyone can back-find one belatedly I'll happily claim it as intentional ;-) $\endgroup$
    – Stiv
    Commented Sep 24, 2021 at 6:12
  • $\begingroup$ I was thinking of rot13(Graarffvar, juvpu vf anzrq nsgre Graarffrr, ohg sbe fbzr ernfba gurl pubfr "Gf" sbe gur flzoby, juvyr gur fgngr vf "Ga". Abgnoyl, Pnyvsbeavn nyfb unf na ryrzrag anzrq nsgre vg, ohg Pnyvsbeavhz hfrf "Ps" orpnhfr "Pn" jnf nyernql gnxra.) $\endgroup$ Commented Sep 24, 2021 at 15:32

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service and acknowledge you have read our privacy policy.

Not the answer you're looking for? Browse other questions tagged or ask your own question.