There are four main types of trends of the periodic table: atomic radius, electron affinity, electronegativity, and ionization energy. All of these trends each have a common set pattern for groups and periods of the periodic table. Electron affinity, electronegativity, and ionization energy all increase across periods from left to right and decrease down groups from top to bottom. While the atomic radius as well as patterns of when atoms become ions decrease across periods from left to right and increase down groups from top to bottom. All of these trends have to do with the attraction of electrons. Each of these trends is affected by at least two of the three variables that will affect each trend. These variables include nuclear charge, atomic radius, and the shielding effect. Electron affinity, electronegativity, and ionization energy can all be explained with the three variables listed above. Atomic radius can be explained with the shielding effect and the nuclear charge.
All of the trends have irregulars, some more so than others. Electron affinity and electronegativity show the most irregulars that will not follow the pattern. The noble gases in booth electronegativity and electron affinity will not follow the set pattern or trend for each of these. This is because the noble gases are stable and do not need to and do not want to gain electron or attract other electrons. The noble gases are content to their position.
In the future slides under trends there will be a more in debt description of each of these trends.