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?