Periodic Trends You will know what ionization energy is and how it trends on the periodic table You will know what electron affinity and electronegativity are and how they trend on the periodic table You will know how cations and anions compare in size to their parent atoms

What Are Ions? Ion Definition - An atom or group of bonded atoms that have a positive or negative charge Any process that creates an ion is referred to as ionization. Na + Sodium cation Cl - Chloride anion NH 4 + Ammonium cation SO 3 2- Sulfite anion

Ionization Energy The energy required to remove one electron from a neutral atom = ionization energy A + energy > A + + e - For main group elements …. Ionization energy increases across each period Ionization energy decreases down each group

What determines IE? The greater the nuclear charge, the greater IE (for periods) Greater distance from nucleus decreases IE (for groups You can attempt to take a 2nd and 3rd electron from an atom = 2nd ionization energy and 3rd ionization energy

Electron Affinity The energy produced when an electron is added to neutral atom = electron affinity A + e > A - + energy

Electron Affinity Trend Electron Affinity: The energy release when an electron is added to an atom. Most favorable toward NE corner of PT since these atoms have a great affinity for e-.

Trends in Ionic Size (page book) Cations are always smaller than the atoms they come from. Example: Na + is smaller than Na Anions are always larger than the atoms they come from. Example: F - is larger than F

Ionic Radii vs Atomic Radii

A Closer Look At Ions

Electronegativity Measure of how much an atom can attract electrons Higher electronegativity results in higher number Highest value is Fluorine Lowest value is Francium Proposed by Linus Pauling --- Useful in describing properties of compounds

Electronegativity Chart

Putting it all Together

Alkali metalsAlkaline Earth Metals Braniac Alkali Metals HalogensHalogens 2 Group Properties of Some Main Group Elements Noble Gases