The elements in every column or group on the periodic table (ssss1) share a similarity in their electron configuration that distinguishes them from elements in every other column. This shared property causes the elements in each group to behave in a similar manner during chemical reactions. As will be seen later in this chapter and throughout the book, knowledge of these patterns is fundamental to understanding and interpreting the formation and behavior of minerals, rocks, and other Earth materials. The tendency of atoms to form cations or anions is indicated by the location of elements in columns of the periodic table.

ssss1 Common ionization states for common elements in columns on the periodic table.

Column (group) Ionic charge Description Examples 1 (IA) +1 Monovalent cations due to low first ionization energy Li⁺¹, Na⁺¹, K⁺¹, Rb⁺¹,Cs⁺¹ 2 (IIA) +2 Lose two electrons due to low first and second ionization energy Be⁺², Mg⁺², Ca⁺², Sr⁺², Ba⁺² 3–12 (IIIB–IIB) +1 to +7 Transition elements; lose variable numbers of electrons depending upon environment Cu⁺¹, Fe⁺², Fe⁺³, Cr⁺², Cr⁺⁶, W⁺⁶, Mn⁺², Mn⁺⁴, Mn⁺⁷ 13 (IIIA) +3 Lose three electrons due to low first through third ionization energy B⁺³, Al⁺³, Ga⁺³ 14 (IVA) +4 Lose four electrons due to low first through fourth ionization energy; may lose a smaller number of electrons C⁺⁴, Si⁺⁴, Ti⁺⁴, Zr⁺⁴, Pb⁺², Sn⁺² 15 (VA) +5 to −3 Lose up to five electrons or capture three electrons to achieve stability N⁺⁵, N⁻³, P⁺⁵, As⁺³, Sb⁺³, Bi⁺⁴ 16 (VIA) −2 Generally gain two electrons to achieve stability; gain six electrons in some environments O⁻², S⁻², S⁺⁶, Se⁻², 17 (VIIA) −1 Gain one electron to achieve stable configuration Cl⁻¹, F⁻¹, Br⁻¹, I⁻¹ 18 (VIIIA) 0 Stable electron configuration; neither gain nor lose electrons He, Ne, Ar, Kr

Metallic elementsalkali metalsalkali earths