General Trends in P.T.: • Atomic Number Protons • Mass Number Protons + Neutrons Metals vs. Non-metals Families (Groups) Sub-Levels Atomic Radius increases going down the table. Additional sublevels make radius larger. Atomic Radius decreases going across the table. Same sublevel filling. Larger charge in center (larger nucleus) pulls electrons in more. Addition or subtraction of an electron dramatically effects atomic radius. Changes the balance of the electron interactions. Losing an electron makes the radius decrease. Gaining an electron makes the radius increase. Ionization Energy is the energy necessary to knock off the outermost electron. Elements that hang onto their outer electrons more strongly (higher electrical attraction) have higher Ionization Energies. What trends do you see? How can they be explained? Definition: The pull of an atom on a shared electron. Electrical Force of attraction depends upon: distance b/t charges size of charge So what would the largest force be caused by? What characteristics would the atom have?