In the periodic table different general trends within one group or period can be observed as summarized in Figure 1. While the atomic radius is increasing within one group, it is decreasing when going from left to right within one period. Electronegativity and ionization energy follow the same trends. An increase can be seen within one period, whereas both values decrease moving down within a group.

A period table with arrows at the bottom, top, left, and right side of it, presenting atomic properties and trends within the table. On the top, two arrows are pointing to the right, and indicate the increase in electronegativity and ionization energy, with the increase of the group number. At the bottom, one arrow pointing to the left indicates the increase in atomic radius, with the decrease of the group number. At the left side, one arrow pointing down indicates the increase of atomic radius, with the increase of the period number. At the right side, two arrows are pointing up, indicating the increase in electronegativity and ionization energy, with the decrease of period number.

Figure 1: Trends in the Periodic Table