7Atomic Radius What are the trends on the periodic table? Atomic radius increases going down a group on the P.T.Atomic radius decreases moving left to right across a period.
8Atomic Radius How can these trends be explained? Group Trend Outer electrons occupy higher energy levels; electrons are farther from the nucleusPeriod TrendIncreasing nuclear charge causes atoms to be smaller (left to right); increased pull on outer electrons due to nuclear charge.
9Ionization Energy X + energy X+ + e- Ionization energy – energy required to remove one electron from a neutral atom (first ionization energy)X + energy X+ + e-Measured using isolated atoms in the gas phase.
11Ionization Energy What are the trends on the periodic table? I.E. increases going left to right across a period.I.E increases from bottom to the top of a group
12Ionization Energy How can these trends be explained? Period Trend I.E. increases left to right as a result of increasing nuclear charge; a larger nuclear charge results in stronger attraction for electronsGroup TrendI.E decreases going down a group due to the fact that electrons are in higher energy levels and farther from the nucleus; also due to the shielding effects of inner electrons.
16Electron Affinity Trends Halogens have the highest electron affinities.Fluorine - 1s22s22p5Electron affinity increases moving to the right on the periodic table. (not always & not including noble gases)Carbon – 1s22s22p2Nitrogen - 1s22s22p3Electron affinity increases moving up a group on the p.t. This trend is not as clear as it is for ionization energy. E.A is affected by nuclear charge and atomic radius
17Ionic Radii When atoms become cations, they become smaller. When atoms become anions, they become larger.
18Valence ElectronsValence Electrons – the electrons located in s and p orbitals for main group elementsAtoms gain, lose, or share electrons to in order to have a complete set of s and p electrons.N s22s22p3P s22s22p63s23p3
19ElectronegativityElectronegativity – the ability of an atom to attract electrons in a chemical bond.
20Electronegativity Trends N, O, and the halogens have the highest electronegativitiesElectronegativity increases going left to right across the p.t. up until the halogensElectronegativity increases going up groups on the p.t.
21Periodic PropertiesWhich element (Cs, Hf, Au) has the smallest atomic radius?AuArrange the following elements in order of decreasing electron affinity: C, O, Li, Na, Rb, FF, O, C, Li, Na, Rb
22Periodic PropertiesArrange the following elements in order of decreasing first ionization energy: Li, O, C, K, Ne, FNe, F, O, C, Li, KWhich element in #3 would have the highest second ionization energy and why?Li
23Periodic PropertiesWhich element is the most electronegative among C, N,O, and S?OWhich ion has the smallest radius, K+ or Ca2+?Ca2+