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Questions 2.3.1(a)

Study the pictures in Figure 2.3.1, then answer the questions that follow (Q1 & 2).

  1. Describe the appearance of the following elements in terms of color and physical state.
    1. Fluorine
    2. Chlorine
    3. Bromine
    4. Iodine
  2. What is the general trend (change) in physical state as we move from the lightest member (fluorine) to the heavier members such as iodine?
  3. Study the atomic structures presented in Figure 2.3.2 then answer the following questions that follow.
    Atomic structures of halogens

    Figure 2.3.2: Atomic structures of halogens


    How would you expect melting point (or boiling point) to change as we move from fluorine to iodine?
  4. Halogens have similar properties but are not the same. What feature of atomic structure do all halogens have in common?


Answers to Questions 2.3.1(a)

    1. Fluorine is a pale yellow gas.
    2. Chlorine is a green-yellow gas.
    3. Bromine is a red fuming liquid.
    4. Iodine is a grey solid (crystals) which easily vaporizes on warming.
  2. Physical state changes from gas to liquid then solid.
  3. Melting and boiling points are expected to increase as we move from fluorine to iodine. From fluorine to iodine, physical state changes from gas to solid indicating that melting and boiling points increase down the group.
  4. Seven electrons on the outermost energy level (or require one electron to complete the energy level).