Per NCERT §3.6, which exceptional element is positioned in the s-block (1s¹) but is sometimes placed with halogens because it can also gain an electron to reach noble-gas configuration?
AHelium (He)
BLithium (Li)
CHydrogen (H)
DBeryllium (Be)
Answer & Solution
Correct answer: C. Hydrogen (H)
Per NCERT §3.6, H is shown separately at the top — it can act like Group 1 (losing 1e) or Group 17 (gaining 1e to reach 1s²).
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