Answer;
-Chlorine is more reactive than silicon
Step-by-step explanation;
-As you move across a period, the nuclear charge will increase; the number of energy levels will stay the same, so there is a stronger and stronger attraction for the electrons.
-The electrons are being held more tightly as you move across a period. It becomes more and more difficult to lose electrons and consequently the reactivity of non metals increases as you go from left to right across the periodic table; Therefore; chlorine is more reactive than silicon.