Periodic Properties and Patterns

Atomic radius is defined as ½ the distance between the nuclei of identical atoms that are bonded together.

For questions 1 – 6 arrange the following elements from smallest-to-largest atomic radii.

  1. Ne, N, B, Li, Be, C, F, O ______
  2. K, As, Kr, Ca, Se, Br, Ge, Ga ______
  3. Tl, Ga, B, Al, In ______
  4. Sb, As, Bi, N, P ______
  5. Mg, Ra, Sr, Be, Ca, Ba ______
  6. Xe, In, Sn, Te, Sr, Rb, Sb, I ______
  1. Which element should have the smallest atomic radii (ignore noble gases) ______
  1. What group number is it? ______
  2. What is the name of this group? ______
  1. Which element should have the largest atomic radii? ______
  1. What group number is it? ______
  2. What is the name of this group?______
  1. Of the elements Li, O, C, and F, identify the one with the largest atomic radius and the one with the smallest atomic radius. ______
  1. Of the elements Br, At, F, I, and Cl, identify the one with the smallest atomic radius and the one with the largest atomic radius. ______

Ionization energy: An electron can be removed from an atom if enough energy is supplied, this is called its ionization energy. This can be calculated by A + energy A+ + e- Any process that results in the formation of an ion is referred to as ionization. The energy required to remove one electron from a neutral atom of an element is the ‘first ionization energy’.

For questions 1 – 5rank the following groups of elements from lowest to highest ionization energy

  1. Li, C, Be, F, B, O, N ______
  2. P, Bi, N, Sb, As ______
  3. Cl, Al, Mg, S, Na, P ______
  4. I, F, Br, Cl, At ______
  5. Fr, Rb, Na, H, Li, K, Cs ______
  1. Which element would have the highest first ionization energy (ignoring noble gases)?
  1. Which element would have the lowest first ionization energy?
  1. In the Alkaline Earth Metal Experiment you saw that calcium was much more reactive with water than was magnesium. Explain this in terms of the ionization energy of these two elements.

Information: Outer electron configurations are the final period/energy level that is listed in an elements electron configuration.

Example: Br = 1S22s22p63s23p64s23d104p5 so the last energy level/period is 4s23d104p5

  1. Consider the four hypothetical main-group elements: Q, R, T and X with the outer electron configurations indicated below. Then answer the questions that follow:

Q = 3s23p5R = 3s1 T = 4d105s25p5X = 4d105s25p1

  1. What elements does each of these represent? Q = ___R = ___T = ____X =___
  2. Identify the block location of each hypothetical main-group element:
  3. Which element would you expect to have the highest first ionization energy? ______
  4. Which would have the lowest first ionization energy? ______

Electronegativity is described as the ability of an atom to pulled shared electrons towards its nucleus. As a general rule the smaller the atom the higher its electronegativity. This is due the shared outer electrons being closer to the nucleus so nucleus has a stronger pull on the shared electrons. Notice that halogens have a higher electronegativity value that the noble gases, with fluorine having the greatest electronegativity value of any element.

For questions 1 – 4 put the elements in order from lowest to highest electronegativity value.

  1. Al, Cl, Mg, Na, Ar ______
  2. Rb, H, Li K, Cs ______
  3. Fe, Cs, F, P, Ga ______
  4. At, Br, F, Cl, I ______
  1. Why do the elements of the noble gas family not have an electronegativity value? Describe your answer in terms of electrons.
  1. Elements within the Lanthanide series (so called rare earth elements) of the inner transition metals have very similar electronegativity values. Explain why this may be the case as it relates to their valence electrons.