Presentation on theme: "Ionic & Molecular Nomenclature Nomenclature refers to the terminology of chemical compounds; represents the basic “language” of chemistry Lets start with."— Presentation transcript:
Ionic & Molecular Nomenclature Nomenclature refers to the terminology of chemical compounds; represents the basic “language” of chemistry Lets start with Ionic Nomenclature Because ions combine to form electrically neutral (no charge) compounds, the names for these compounds do not include the number of each ion present The system assumes you know the formula and charge of the ions that make up the compound This may seem confusing at first. Fortunately there are some rules about the charges of ions that can help you out! These rules need to be committed to memory.
Some rules to help you with ionic nomenclature Rule 1: Metals form (+) ions and are monatomic. The charges on ions formed from elements in groups 1, 2 and the upper part of 3 (13) is the same as the group # For example, group 1A has (+1), 2A has (+2), and the upper part, boron, aluminum and gallium have a +3 charge. The ion name is the same as that of the element (Ca +2 = calcium ion ; Na + = sodium ion) Practice: Give the ion, along with its charge, and provide its name Lithium Gallium Barium Francium
Some rules to help you with ionic nomenclature Rule 2: With the exception of Cd, Zn and Ag, which have only one charge, the rest of the metals can form ions with multiple charges. These are represented by a Roman numeral after the ion name For example, Fe +2 is iron (II) and Fe +3 is iron (III), zinc is always Zn +2 You will want to commit Cd +2, Zn +2 and Ag + to memory Practice: Give the name of the following ions Co +2 and Co +3 Mo +3 and Mo +6 Cd +2 Cu + and Cu +2
Some rules to help you with ionic nomenclature Rule 3: Non-metals form (-) ions charge can be predicted by position on PT Halogens (7A or 17) are 1 away from noble gases so they form -1 ions The oxygen family (6A or 16) is two spots away from noble gases so they form -2 ions The nitrogen family follows the same trend as well (-3 ions) The monatomic ions have the –ide ending Example: O -2 is oxide, P -3 is phosphide, Br -1 is bromide Practice: Give the names of the following ions Se -2 Te -2 N -3
Polyatomic Ions Polyatomic refers to “many atoms” that are bonded together that act as one ion There is no common trend for the most part, so these are best committed to memory I will give you some common ones I want you to know Names of polyatomic ions are not changed Example: K + and SO 4 -2 form K 2 SO 4 and is properly named potassium sulfate