Which of the following molecules has a triple bond in its structure?

Step 1: Analyze the question We need the molecule whose Lewis structure contains a triple bond (three shared electron pairs between two atoms).

Step 2: Concept Atoms share electrons to complete their octet (or duet for hydrogen). The number of bonds between atoms depends on how many electrons each atom needs.

Step 3: Check each option

• A. CH₄: Carbon has 4 valence electrons and bonds with 4 hydrogen atoms, each by a single bond (C-H). No triple bond.
• B. NH₃: Nitrogen has 5 valence electrons. It forms 3 single bonds with 3 hydrogen atoms and keeps one lone pair. No triple bond.
• C. N₂: Each nitrogen atom has 5 valence electrons and needs 3 more to complete its octet. Each atom shares 3 electrons, so the two atoms share 3 pairs: :N≡N:. This is a triple bond.
• D. O₂: Each oxygen atom has 6 valence electrons and needs 2 more. They share 2 pairs: O=O. This is a double bond.

Step 4: Answer The molecule with a triple bond is N₂, which is option C.

Tip: Link the number of bonds to the electrons needed to reach 8:

• Needs 1 more electron (H, Cl, F): single bond
• Needs 2 more (O): double bond
• Needs 3 more (N): triple bond

N₂ has a very strong triple bond, which is why nitrogen gas is so unreactive and makes up about 78% of the air.