In Chapter 6 we discussed quantum mechanics and how electrons arrange themselves in atoms. In addition to explaining the electronic properties of the atom, quantum mechanics can also explain the arrangement of elements in the periodic Table.
7.1 Development of the Periodic Table
The periodic table is broken down into two main groups. Group “A” or the main group elements, and Group “B” or the transition metals
7.1 Main Group Elements and Transition Metals
Periodic Trends allow chemists to generalize properties of atoms and they will be a big help in explaining the concepts of chemical bonding in the next chapter. The first trends we will investigate are atomic and ionic radii.
7.3 Atomic Radii
7.3 Ionic Radii
With knowledge of how the sizes of atoms and ions are determined, we can list the correct order of the species of an isoelectronic series, or a series containing the same number of electrons.
7.3 Isoelectronic Species
The size of an atom gives an indication of how far away an electron is from the nucleus. Ionization Energy is defined as the energy required to remove an electron from an atom, so having a solid foundation on the size of an atom, we can now investigate how much energy it will take to remove an electron from an atom.
7.4 Ionization Energy Part 1
7.4 Ionization Energy Part 2
We saw with ionization energy that we can measure how much energy is required to remove an electron. We can also look into what will happen when an electron is added to an atom. Will adding an electron make the atom more or less stable? The amount of energy associated with the gain of an electron by a gaseous atom is its Electron Affinity.
7.5 Electron Affinity
Electronegativity does not show up in our text until Chapter 8, but I want to introduce it with all the other periodic trends. Electronegativity is defined as the ability of a given atom in a molecule to attract electrons to itself.
We discussed spin quantum numbers and recognized that electrons have a spin moment associated with them. As a consequence, they can be attracted or repelled to a magnetic field. The magnetic properties of an atom can be explained by looking at the valence electrons and determining if any of the valence electrons are unpaired.
7.6 Magnetic Properties