Question

$O_2$, which has a double bond, would have how many sigma and how many pi bonds?

Answer 1

$O_2$ has $1$ sigma bond and $1$ pi bond.

As we know, the $O_2$ molecule's Lewis structure shows a double bond between three two oxygen atoms.

A double bond is comprised of $1$ sigma bond and $1$ pi bond. A triple bond has $1$ sigma and $2$ pi bonds.