Answer
Each $Cl$ initially has 7 valence electrons.
Work Step by Step
The electron configuration of $Cl$ is $$[Ne]3s^23p^5$$
The valence electrons are in the $3s$ and $3p$ subshells. Subshell $3s$ has 2 electrons, and subshell $3p$ has 5 electrons.
Therefore, each $Cl$ initially has 7 valence electrons.
Also, looking at the diagram below, we see that on the left side, each $Cl$ is represented by 7 dots. So it also shows each $Cl$ initially has 7 valence electrons.
