unit 5 ib chem

• Hydrated Crystals


  Salts that have apsorbed water into their crystal Lattice Structure
• Anhydrous Salts


  Used as drying agents to absorb water (dessicants)
• Hydrated compounds


  Named as ionic compounds with the addition of the water
• Prefix for hydrated compounds

  The prefix used is the same as for covalent compounds
• The dot is NOT for multiplication
• Experimental Errors


  • Systematic Errors
  • Random Uncertainties
• Significant Figures in Measurements

  • Values compared to a marked (ruler, graduated cylinder,...) should be recorded and estimated past the smallest mark
  • Uncertainty is the smallest mark
• Electronic instruments


  Record exact value reported and the uncertainty is of the last digit
• ionization energies decrease as we go across a period because the nuclear charge increases but so does the number of protons which makes it easier to remove an electron.
• ionization energies increase as we move down a group because there are more electron shells that can shield the outermost electrons, making it harder to remove them.
• the first ionization energy is the amount of energy required to remove one mole of electrons from one mole of gaseous atoms
• Bonding


  Atoms bond to achieve ability
• Three types of Bonding

  • Ionic
  • Covalent
  • Metallic
• Octet Rule


  A concept of chemical bonding theory based on the assumption that atoms tend to have either completely or full valence shells
• Ionic Bonding


  • Occurs between a metal and a nonmetal or polyatomic ion
  • Holds chemical compounds together
• Covalent Bonding


  • Occurs between two or more non-metals
• Metallic Bonding


  • Occurs between metals
• Physical Properties of Ionic vs. Covalent Compounds

  • Ionic Compounds: Solids are usually hard, typically soluble in water, conduct electricity in molten or aqueous state, have high melting and boiling points
  • Covalent Compounds: Solids are usually soft, typically soluble in non-polar substances, do not conduct electricity, have low melting and boiling points
• Ionic Bonds


  Form between a metal and a nonmetal, the metal loses electrons to the nonmetal which gains electrons
• The cation is the atom which loses electrons, the anion is the atom which gains electrons
• Ionization


  The process where an atom loses or gains electrons to form an ion
• Ionization of Sodium and Chlorine

  • Sodium loses an electron to form a positive sodium ion, Chlorine gains an electron to form a negative chloride ion
• Sodium Chloride


  Formed from sodium cations and chloride ions, held together by electrostatic attraction in a crystal lattice
• Naming Ionic Compounds


  1. Write the name of the cation first, then the name of the anion with -ide suffix

  2. For compounds with transition metals, write the charge of the cation in Roman numerals in parentheses
• Naming Ionic Compounds


  • NaCl - Sodium Chloride
  • Al2O3 - Aluminum Oxide
  • FeCl3 - Iron(III) Chloride
• Writing Ionic Compound Formulas

  1. Determine the charges of the ions

  2. Combine the ions in the simplest whole number ratio to make a neutral compound

  3. Swap the numbers and drop to make subscripts
• Writing Ionic Compound Formulas

  • MgCl2 - Magnesium Chloride
  • Al2O3 - Aluminum Oxide
  • BaBr2 - Barium Bromide
• Transition Metals


  • Can have variable charges, not just one fixed charge
  • Can form multiple ionic compounds with the same nonmetal
• Naming Ionic Compounds with Transition Metals

  1. Write the name of the cation first

  2. Include the charge of the cation in Roman numerals in parentheses

  3. Write the name of the anion with -ide suffix
• Naming Ionic Compounds with Transition Metals


  • FeCl2 - Iron(II) Chloride
  • CuO - Copper(II) Oxide
  • VCl2 - Vanadium(II) Chloride
• Metallic Properties


  Result from the arrangement of particles on the atomic level in metals, with a crystal lattice of metal cations and a "sea of electrons" that can move freely
• Metallic Bonding


  • Atoms in a metal are held together by the electrostatic attraction between the metal cations and the delocalized valence electrons
  • Allows for malleability and ductility as the cations can slide past each other
• Electrical Conductivity


  Metals always have moving charges (the "sea of electrons") that can conduct electricity, ionic compounds can conduct in molten or aqueous state, covalent compounds generally do not conduct
• Thermal Conductivity


  Metals have high thermal conductivity as the delocalized electrons can easily transfer kinetic energy, covalent compounds have low thermal conductivity as their particles are localized
• Metallic bonding is stronger than ionic bonding, which is stronger than covalent bonding
• the third ionization energy is less than the second ionization energy because removing three electrons requires less energy than removing only two electrons.
• The second ionization energy is the amount of energy required to remove two electrons from one mole of gaseous atoms
• As we move left to right across a period, the atomic radius gets smaller meaning that the outermost electron is closer to the nucleus making it easier to remove that electron.
• the first ionization energy is always greater than the second ionization energy because it takes more energy to remove two electrons from an atom than just one.
• Trends in ionization energies can also be explained by looking at atomic radius. As we move up a group, the atomic radius gets larger meaning that the outermost electron is farther away from the nucleus making it harder to remove that electron.