I guess you want to add to only the clicked item the class. However, it always adds the class to the last one. That's because i is accessed after the end of the for, so it always contains 165. Do this to solve your problem:
var i=1;
for(i; i <=165; i++){
jQuery(".tekAlan"+i).click(function() {
jQuery(this).addClass("tekAlanSecildi");
});
}
jQuery(this)
is a reference of the element affected by the event (in this case, click
)