This is a model of a chlorine atom. how likely is it that this atom would want to bond with another atom?

This atom REALLY wants to bond with another atom!
Lets think of the octet rule.
The octet rule is a scientific rule about atoms that states that the valence shell, (the outer most shell, the shell closest to the outside), wants to have 8 electrons in it. This outer orbital or valence shell, wants to have 8 electrons so bad because it wants to fulfill its octet rule.

Now, this atom of chlorine has 7 electrons in the outer shell. This is why it REALLY wants to bond. It is so close to fulfilling its octet rule, it is only one away.

Hope this helped!