quizlet.com › 312489091 › periodic-trends-worksheetPeriodic Trends Worksheet Flashcards | Quizlet A)Atomic Radius (Excluding noble gases) B)First ionization energy C)Electronegativity A)Decrease B)Increase C)Increase What trend in atomic radius occurs down a group on the periodic table?What causes this trend? Increases down group because energy level shells are added What trend in ionization energy occurs across a period on the periodic table?