2.7 Monatomic ions- ions made of 1 atom Group 1 lose 1 e- 1 + Group 2 lose 2e- 2 + Group 13 lose 3 e- 3 + Group 14- bonds covalently Group 15 gain 3 e- 3 - Group 16 gain 2 e- 2 - Group 17 gain 1 e- 1 - Group 18 Noble gases- inert
Transition elements have more than 1 oxidation state; To distinguish change the ending -ic ending is higher oxidation number ferric Fe 3+ -ous ending is lower oxidation number ferrous Fe 2+ ** Problem is knowing where to start
OR Use Roman Numerals iron (II) Fe 2+ iron (III) Fe 3+ Exceptions: silver is always Ag 1+ cadmium & zinc are always 2 + Ex: Iron (III) chloride
Polyatomic Ions: groups of ions with a charge hypo- -ite lowest # O -ite ending lower # O -atehigher # O hyper- -ate highest # O EX: nitrate NO 3 - nitrite NO 2 -
6.4 Binary compound- compounds made of 2 element types To write: Always write metal 1 st Write symbols w/charges Drop charges Cross superscripts to other subscripts
To name: Name metal (if transition MUST indicate which w/ Roman Numeral) Then nonmetal w/ ide ending NaCl KBr FeCl 3
Ternary Ionic Compounds: contain polyatomic ions To write: Always write metal or cation 1 st Write symbols w/charges Drop charges Cross superscripts to other subscripts **If there will be more than 1 polyatomic ion use ( ) around the polyatomic ion formula
To name: Name + ion or metal (if transition must indicate oxidation number) 1 st Name nonmetal Name polyatomic ions NaNO 3 Fe(NO 2 ) 2 Fe(NO 3 ) 3
2.7 Naming molecular compounds: 1. Use prefixes a. mono –1 b. di – 2 c. tri – 3 d. tetra – 4 e. penta –5 f. hexa – 6 g. hepta – 7 h. octa – 8 i. nona – 9 j. deca – 10 Ex: N 2 O 5
Naming acids Binary acids: H plus 1 other element hydro ____ ic acid HClhydrochloric acid HF HBr HI H 2 S H 3 N Oxyacids: H plus a polyatomic with oxygen Look at polyatomic ion ending -ate _____ic acid -ite _____ ous acid
The formula for a Hydrate Hydrate – compound with a specific # of water molecules bound to its atoms Naming: name salt prefix hydrate CaCl 2 2H 2 O calcium chloride dihydrate Prefixes are the same as those used for covalent compounds (see page 338 for review) Anhydrous – without water used to store water or as drying agents Used to store solar energy i.e. sodium sulfate decahydrate
Compound Nomenclature Binary compound Metal present yes no yes Use prefixes Does the metal form more than one cation? Use element name Use element name with proper Roman numeral no Polyatomic ion or ions present? yes Use the polyatomic name as appropriate noyes no Not established no yes Use Acid naming rules Is hydrogen the cation?
Acid Nomenclature Is oxygen in the anion yes no Hydro- + anion root + -ic Hydro(anion root)ic acid anion or element root + -ous (root)ous acid anion or element root + -ic (root)ic acid Check the ending of the anion name -ite-ate
Naming Compounds and Writing Formulas Acids start with hydrogen IF there is no oxygen, you name it with hydro – root – ic acid IF there is an oxygen, you change the ending of the polyatomic name - ate becomes –ic acid - ite becomes – ous acid Both contain polyatomics – KNOW them! Both formulas have to balance to zero Ionic compounds start with metals IF the metal is a transition metal, or P block metal then a Roman numeral is used to represent the charge (basically everything except the S block, Al, Zn, Cd, Ag, & Ga). Polyatomic names are not changed – just use the name. Covalent compounds start with nonmetals or metalloids Prefixes are used to identify the number of atoms for an element NEVER use mono on the first element The prefixes are: mono, di, tri, tetra, penta, hexa, hepta, octa, nona, and deca Binary compounds 1 st element uses name 2 nd element named with root and -ide You MUST KNOW your elements and their symbols!
Common Mistakes Not KNOWING the 14 polyatomics – correct formula and charges Not KNOWING the charges of elements based on the periodic table. Alkali metals are 1+, alkaline earth metals are 2+, aluminum is 3+, nitrogen group is 3-, oxygen group is 2-, halogens are 1-. Transition metals (except zinc, cadmium, and silver) and metals in the P block have more than 1 charge. Not putting the parentheses around hydroxide when there is more than 1. OH 2 is water; (OH) 2 is 2 hydroxides Not simplifying (if the charges are the same, no subscripts are needed) Not using roman numerals correctly in the names.