GREY'S ANATOMY - "Physical Attraction... Chemical Reaction" - George and Izzie's romantic chemistry is put to the test, as Derek asks for more than a physical connection from Meredith; much to his own surprise, Mark develops a crush on a fellow surgeon, and Callie's role as Chief Resident is placed in jeopardy after she delegates much of her job to Bailey, on "Grey's Anatomy," THURSDAY, NOVEMBER 8 (9:00-10:02 p.m., ET) on the ABC Television Network. (ABC/RON TOM) JUSTIN CHAMBERS, ELLEN POMPEO