Chemical Bonding and Periodic Trends Periodic Trends Assignment

Chemical Bonding and Periodic Trends

Periodic Trends • Assignment for weekend; – Identify the periodic trends for each of the following properties: • • • Atomic radius density Boiling/melting point First ionization energy Electronegativity – Be able to make comparisons!!!! By Monday!!

Using your notes… 1. 2. 3. 4. 5. 6. 7. 8. 9. Larger atom: hydrogen or sodium Larger atom: nitrogen or florine Higher ionization energy: K or Cu Higher ionization energy: Ca or Ba Higher electronegativity: Be or O Higher electronegativity: O or Se Higher Density: Cs or Os Higher boiling point: S or Cl EC – highest electronegativity: , lowest ioniz. Energy

Using Periodic properties for bond predictions • • • Metal to metal: Metal to non-metal Non-metal to non-metal (similar) Non-metal to non-metal (different) Electronegativity difference 0 < covalent. 5 < polar covalent < 1. 6 ionic (roughly)

Other Trends

Properties • Favorite substance • Favorite use • Engineering techniques/production

Using Dot Diagrams to predict bonding What is a Stable Electron Configuration? ? FULLOREIGHT Using DOT diagrams to represent/predict bonding

Using Dot Diagrams to predict bonding • Valence Shared Electron Pair Repulsion Model – VSEPR – Used to predict Molecular Shapes and there fore properties

Bond ing Lab • Work to fill out table • Check book or internet for official names to the shapes of your compounds • Be sure you can identify the central atom, if one, of each molecule • BE SURE to clean table before you open bags!!!!!

Shapes • Make a list of molecular shapes from Chapter 12 • Sketch each shape in you notebook!!!

Bonding comparison • • TYPES: NPC PC I M Conductivity (solid and aqueous) Melting point, boiling point Solubility • sodium chloride, sucrose, copper sulfate, glucose, starch, iron filings, manganese IV dioxide, charcoal • Data table: substance, bond type, prediction/observation