Ionic compounds are composed of positive ion called a cation bonded to a negative ion called an anion. The charges of the periodic table are important when determining the molecular formula for ionic compounds.
Major Classification Types of the Period Table
Recall that the elements of the periodic table are labeled as metals, non-metals, and metalloids. The Periodic Table provides you with the element symbol, element number, the atomic mass and the atomic number.
Generally, metals lose electrons to become cations, while non-metals gain electrons to become anions. We disregard talking about the ionic charges of metalloids because they share characteristics of both metals and non-metals.
Main Group Charges
Elements gain and lose electrons in order to be more like the noble gases and have the same number of electrons as them.
Most main group elements possess one charge. Notably exceptions are lead (Pb) and tin (Sn), which have charges of +2 and +4.
Transition Metal Charges
The Transition Metals and Inner Transition Metals, of which are further divided into Lanthanides and Actinides are sometimes referred to as the Group B Elements.
Transition metals tend to have varying positive charges. The most common charges for the first row of transition metals are provided as:
The checkmarks in red represent the most common charge for the given transition metal.
Once you’ve learned the general trends in element charges you’ll be able to deal with nomenclature where you learn how to name ionic compounds, polyatomic ions and eventually covalent compounds.