Here's why:

* Electronegativity is the ability of an atom to attract electrons towards itself in a chemical bond.

* Chlorine is located in Group 17 (halogens) of the periodic table, which are known for their high electronegativity. This is because they have a strong pull on electrons due to their small atomic size and high nuclear charge.

* Carbon is located in Group 14 (carbon family) and has a lower electronegativity compared to chlorine.

You can remember this by the general trend on the periodic table: electronegativity increases from left to right across a period and decreases down a group.