Molecule "a" is O2
The O2 Lewis structure has a double bond between two oxygen atoms. consistent with the octet rule, oxygen atoms have to bond twice. The O2 molecule is diatomic, meaning that two atoms of identical elements are connected in a pair.
What is an octet rule?
The octet rule may be a chemical rule of thumb that reflects the theory that main-group elements tend to bond in such a way that each atom has eight electrons in its valence shell, giving it the identical electronic configuration to a noble gas.
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