Chapter 9 Chemical Names and Formulas 9.1 Naming Ions 9.2 Naming and Writing Formulas for Ionic Compounds 9.3 Naming and Writing Formulas for Molecular Compounds 9.4 Naming and Writing Formulas for Acids and Bases 9.5 The Laws Governing Formulas and Names

9.1 Naming Ions 1. Monotomic Ions – A single atom with a positive or negative charge resulting from the loss or gain of electrons. 2. Cations – When metals in groups 1A, 2A, and 3A lose electrons, they form cations with positive charges equal to their group number. 3. Anions – When nonmetals from groups 5A, 6A, and 7A gain electrons, they form anions with negative charges equal to their group number minus eight. The name changes leaving the root of the name and adding a –ide to the end CW – try a few – F, Cl, S, O, N, P, I 4. Group 4A and 8A, usually do not form ions 5. Transition Metals – the charges of the cations of many transition metal ions must be determined from the number of electrons lost. Transition metals form cations with different ionic charges. Two methods are used to names these ions. a. Stock System b. Classical System

The Stock System: The preferred method Roman numerals are placed in a parentheses after the name of the element to indicate the numerical value of the ions charge. Lets try a few Cu, Fe, Hg, Pb, Mn, Sn

Classical System Uses a root word with different suffixes at the end of the word. The root word of some elements may differ from the name you are use to using. The suffix –ous is used to name the cation with the lower ionic charge. The suffix –ic is used to name the cation with the higher ionic charge. Lets try a few – Fe, Pb, Cu, Mn, Co, Cr Note: there are a few transition ions that have only one charge – Ag, at +1 and Cd and Zn at +2

Polyatomic Ions: These ions are composed of more than one atom. Naming Hyper _____ ate __________ate __________ite Hypo_____ite Turn to page 257 of your text and lets look at a few - When polyatomic ions begin with Hydrogen the overall charge of the ion is changed and then named Hydrogen _____ate If there is more then one H a prefix is added to the Hydrogen when naming. Lets try a few Hydrogen Carbonate, Dihydrogen Phosphate

Now lets put it together – Binary Ionic Compounds The total oxidation number of the pair of atoms must equal zero. To create a neutral compound the cations must equal the anions. This is done by selecting the proper number of each ion to create a neutral or zero charge on the compound. The proper number of ions is expressed as a subscript following the atom. Remember to reduce the values to their lowest whole number ratio. In naming the atom simply name the cation then name the root of the anion and add an –ide ending. Lets try a few!

B. Polyatomic Ions Polyatomic ions are treated much like binary ionic compounds. That means that the oxidation number of the polyatomic ions must create a neutral overall charge when added to another atom. It is kind of a package deal! The number of polyatomic ions needed to balance the formula is put as a subscript outside the polyatomic ion. Lets try a few Magnesium Sulfate, Calcium Nitrate, Aluminum Oxalate