Bonds, IMF, and Physical Properties How we can predict the behavior of molecules!

Objectives When given a molecule, determine the type of bond that holds the atoms together and the type of IMF that holds different molecules together. To describe the characteristics of any molecule, when given the type of bond –MP/BP- Type of Particles –Physical State- Solubility –Conductivity- Keywords To compare and contrast a polymer and a monomer To identify what type of monomer makes up: –Proteins- Starches –Nucleic acids

Metallic Compounds Examples: Al, Cu, Fe Types of atoms: cations in sea of electrons Electrons are: In a community IMF’s = metallic bonds Strength of IMF Very strong Physical state – all solids except Hg Melting/Boiling Pts. – variable – depends on charge and size Solubility in water – Not soluble Conductivity – conduct as solids or liquids Keywords: ductile, malleable, electron sea model, delocalized electrons

Ionic Compounds Examples: NaCl, MgO Types of atoms: Metal and Non-metal –Groups 1-3 and trans metals are 1 st element Electrons are: Transferred or Exchanged IMF’s = Ionic bonds Strength of IMFs: Strongest Physical state – crystalline solids, brittle Melting/Boiling Pts. – very high Solubility in water – most are soluble Conductivity – conduct as liquids or when dissolved in water. Key words: electrostatic, lattice, brittle, hard

Polar Covalent Compounds Examples: H 2 S, HCl, H 2 O Types of atoms: usually 2 or more non-metals (e-neg difference between 0.5 to 1.7) Electrons are: unequally shared, causing areas of partial charges IMF’s = Dipole-Dipole and maybe Hydrogen bonds if Hydrogen is present Strength of IMFs: Mid range Physical state – usually gases or liquids at room temperature, but can be solid –Depends on molecular weight (MW) Melting/Boiling Pts. – low to medium Solubility in water – most are soluble Conductivity – Do not conduct

Non-Polar Covalent Compounds Examples: O 2, CH 4, CO 2 Types of atoms: 2 or more non-metals (both non-metals are close together or have similar e- neg) Electrons are: Equally shared IMF’s = Van Der Waals (Dispersion) Strength of IMFs: Weakest Physical state – usually gases at room temperature, can be liquids, and rarely solids –Depends on molecular weight (MW) Melting/Boiling Pts. – very low to low Solubility in water – Not soluble Conductivity – poor to non conducting

Polymers A polymer is a long, chain like molecule that is made up of repeating units, called monomers. Polymers are a specific type of covalent bond Many important molecules necessary for life are polymers. –Proteins are made up of amino acids –Starches are made up of sugars –Nucleic acids are made up of sugar, nitrogenous base, and phosphate group

Proteins Add 1000s of individual amino acids → Proteins

Nucleic Acids 100s (sugar + nitrogenous base + PO 4 ) → nucleic acid 2 types of nucleic acids DNA RNA Made up of repeating monomers of Sugar Base Phosphate (PO 4 )

Starches Add 1000s sugars → starch Starches are sugars the body uses to store energy. Different starches have different monomers Starch: The glucose face the same way Cellulose: The glucose alternate Glycogen: The glucose fold up

Polymerization Animation