1 (1A) 2 (2A) 16 (6A) 18 (8A)
I gave my students this multiple choice question: According to the periodic table, argon is found in what column?

Only one answer is correct among these 4 choices:
- 1 (1A)
- 2 (2A)
- 16 (6A)
- 18 (8A)

Could you tell me which one is correct?

18 (8A)