Advanced Placement Chemistry 1987 Free Response Questions

5) Use the details of modern atomic theory to explain each of the following experimental observations.

(a) Within a family such as the alkali metals, the ionic radius increases as the atomic number increases.

(b) The radius of the chlorine atom is smaller than the radius of the chloride ion, Cl¯. (Radii: Cl atom = 0.99 Å; Cl= ion = 1.81 Å)

(c) The first ionization energy of aluminum is lower than the first ionization energy of magnesium. (First ionization energies: ₁₂Mg = 7.6 ev, ₁₃Al = 6.0 ev)

(d) For magnesium, the difference between the second and third ionization energies is much larger than the difference between the first and second ionization energies. (Ionization energies, in electron-volts, for Mg: 1st = 7.6, 2nd = 14, 3rd= 80)

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