Each element is placed in a specific location because of its atomic structure. As with any grid, the periodic table has rows left to right and columns up and down. Each row and column has specific characteristics. For example, magnesium Mg and calcium Mg are found in column two and share certain similarities while potassium K and calcium Ca from row four share different characteristics. Magnesium and sodium Na also share qualities because the are in the same period similar electron configurations.
Title Trends in Group 1 Note: Even though Hydrogen will appear above Lithium on the periodic table it is not considered a part of Group 1. Group 1 elements are known as Alkali Metals. They are called s-block elements because their highest energy electrons appear in the s subshell. Progressing down group 1, the atomic radius increases due to the extra shell of electrons for each element.