Question

What kind of chemical bond is formed when an equal exchange of electrons occurs?

Answer 1

A covalent bond is when two atoms share valence electrons to obtain a full valence shell, which translates into more stability.

For instance, consider `CO_2`

or more simply,

In this configuration, each atom has an octet (since the oxygen atoms don't have formal charges, it's conventional to assume they each have two lone pairs in addition to the double bonds).

In the orbital diagram, the carbon atom has two `"sp"` hybridized orbitals and two unhybridized `"p"` orbitals. The former are used to create `sigma` bonds and the latter to create `pi` bonds with oxygen atoms to optimally share electrons.