The prefix 'di' means two. Hence two atoms make up a diatomic molecule.
Hope this helps!
Both carbon and lead belong to Group IV elements, and thus they have the same number of valence electrons.
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each of the other options, the two elements belong to different groups,
and thus they do NOT have the same number of valence electrons.
I hope this helped you, please tell me if I am correct or not <3
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