Unit 3 Standards Review

Gap-fill exercise

Fill in all the gaps, then press "Check" to check your answers. Use the "Hint" button to get a free letter if an answer is giving you trouble. You can also click on the "[?]" button to get a clue. Note that you will lose points if you ask for hints or clues!

Covalent Bonding



  1. Students know atoms can combine to form molecules by sharing electrons to form bonds.
  2. Students know chemical bonds between atoms in molecules such as H2, CH4, NH3, H2CCH2, N2, Cl2, and many large biological molecules are .

    • Test Hint: The word "molecule" ALWAYS refers to bonding.
    • When nonmetals bond with nonmetals, the bond will be
    • When metals bond with metals, the bond will be
    • When metals bond with nonmetals, the bond will be

  3. Students know the atoms and molecules in liquids move in a pattern relative to one another because the intermolecular forces are too to hold the atoms or molecules in a solid form.
  4. Students know how to draw Lewis dot structures.

    • Lewis dot structures for individual atoms can have no more than dots in the notation.
    • Elements bond so that each element obtains the electron configuration of a gas. For hydrogen, this means electrons; for other nonmetals it means electrons (sometimes referred to as the rule)
    • A covelent bond represents one of shared electrons
    • The HONC rule says that in covalent bonding,

      • Hydrogen and the Halogens form bond
      • Oxygen (and sufur) form bonds
      • Nitrogen (and phosphorus) form bonds
      • Carbon (and silicon) form bonds



  5. Students know large molecules (mers), such as proteins, nucleic acids, and starch, are formed by repetitive combinations of simple subunits (mers).
  6. Students know the bonding characteristics of that result in the formation of a large variety of structures ranging from simple hydrocarbons to complex polymers and biological molecules.
  7. Students know amino acids are the building blocks of .