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Nomenclature. Chemistry Unit Science 10. Nomenclature. Ask yourself, “Is it binary or polyatomic ?” If it is binary , it is made up of 2 elements (straight from the periodic table). Ex: LiF, HCl, MgO, Mg 3 N 2 , AlH 3 Only 2 element symbols in the formula. Binary Compounds.
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Nomenclature Chemistry Unit Science 10
Nomenclature • Ask yourself, “Is it binary or polyatomic?” • If it is binary, it is made up of 2 elements (straight from the periodic table). • Ex: LiF, HCl, MgO, Mg3N2 , AlH3 • Only 2 element symbols in the formula
Binary Compounds • There are 2 types of binary compounds: • Binaryionic (a metal and a non-metal) • Binarycovalent (2 non-metals)
Type 1: Binary Ionic (2 elements, 1 metal, 1 non-metal) • To name a binary ionic compound: • themetal always comes first. • the non-metal’sending gets changed to ide. • if it is a transition metal you need to decide which charge it is. • balance of total negative and positive charge.
Type 1: Binary Ionic (2 elements, 1 metal, 1 non-metal) • Going from formula to name is easy! e.g.LiF: Lithium + Fluorine Lithium Fluorine Lithium Fluor Lithium Fluoride This compound’s name is Lithium Fluoride drop the non-metals ending and replace with the appropriate ending… which is? …Write metal first, non-metal second
Type 1: Binary Ionic (2 elements, 1 metal, 1 non-metal) • Going from name to formula requires you to balance the charges of your ions… e.g.Beryllium Hydride: Beryllium+ Hydrogen So the formula would be BeH2 · Be · · H H · Beryllium will give one of its electrons to the hydrogen, but it is still not balanced… Now that all the elements are in their most stable forms (balanced), we can write the formula…
Type 1: Binary Ionic: Transition Metals (2 elements, 1 metal, 1 non-metal) • Transition metals: Check your periodic table of ions to see what the charges of each Transition metal has. • Balance charges on metal and non metal as per usual
Type 1: Binary Ionic: Transition Metals THE ONLY DIFFERENCE WITH TRANSITION METALS TOOUR OTHER BINARY IONICCOMPOUNDS IS THAT THEY CAN HAVE MORE THAN 1 CHARGE WE DO THEM THEEXACT SAME (2 elements, 1 metal, 1 non-metal) Iron (II) has a 2+ charge whereas Iron (III) has a 3+ charge • Ex: Iron (II) sulphide Fe 2+ + S 2- FeS • Ex2: AuF3 So which gold will fit with our equation? Au(I) or Au(III) are the two different charges of gold Will Au+ + F- or Au3+ + F+give AuF3 - use your lewis transfer diagrams to decide Au (I) has a 1+ charge whereas Au (III) has a 3+ charge
Type 2: Binary Covalent (2 elements, both non-metals) • To name a binary covalent compound: • use prefixes to indicate how many of each there are. • Prefixes: mono, di, tri, tetra, penta, hexa, hepta, octa, nona, deca. • also ends in ide. • balance using valence numbers (groups)
Type 2: Binary Covalent (2 elements, both non-metals) • To go from formula to name: e.g. HCl - 1 Hydrogen, 1 Chlorine The first element doesn’t get the mono prefix if it is just one. It does only if its more than one. Hydrogen monochloride
Type 2: Binary Covalent (2 elements, both non-metals) e.g. N2O3 - 2 Nitrogen + 3 Oxygen • prefixes:2 nitrogen=di, 3 oxygen = tri • oxygen becomes oxide So the name becomes:Dinitrogentrioxide
Type 2: Binary Covalent (2 elements, both non-metals) • Going from name to formula is just as easy with covalent compounds, since the name tells you how many of each you have • e.g. nitrogen trichloride = NCl3 tetraphosphorus hexaoxide = P4O6 dinitrogen pentoxide = N2O5 sulfur hexafluoride = SF6 It’s just that simple!!!
Polyatomic • What does it mean to be polyatomic? More than 2 elements in a compound. • You will find examples of these on the back of your periodic tables.
Naming Polyatomic Compounds • these do not end in ide *most end in ate or ite. • you decide on how many of each by balancing positive and negative charges(these compounds typically exist as ions) the same as your binary ionic compounds are balanced • if there is more than one of the polyatomic ion, it must be written in brackets with the subscript outside the bracket • Polyatomic ions do not use prefixes THEY ACT THE EXACT SAME AS YOUR BINARY IONIC COMPOUNDS
Naming Polyatomic Compounds • e.g. Li2SO4 SO4 is an ion with a -2 charge, so it wants to gain two electrons to get its -2 charge. It will take one electrons from each of the 2 lithium allowing them to form an ionic bond. • e.g. Ca(NO3)2 so we have 2 NO3’s NO3 has a -1 charge, so it wants 1 electron, but calcium has 2 to give up so we need two NO3 to balance the formula.
Polyatomic Ions: the Ate or the Ite • note that the ending of polyatomic ions depends on how many O’s there are • more O’s is ate. • fewer O’s is ite. • e.g. SO4-2 sulfate – 4 O’s SO3-2 sulfite – 3 O’s
Writing Polyatomic IonsGroup 17 (Halogens) • these can all form 4 different ions when they bond with oxygen. • named according to how many O… FO FO2 FO3 FO4 } ite because they have fewer O } ate because they have more O
Writing Polyatomic IonsGroup 17 (Halogens) • these can all form 4 different ions when they bond with oxygen. • named according to how many O… FO> hypofluorite> even fewer O FO2> fluorite FO3> fluorate FO4> perfluorate> even more O
So what am I looking for? • When given a formula or name of a compound how will I know if it is Binary Ionic, Binary Covalent, or Polyatomic? • If the formula/name begins with a metal, you know right away that you are dealing with ions and must balance charges (Binary Ionic, or Polyatomic with metals). • If you see prefixes like di or tri in the name you know it is Binary Covalent (since both ionic and polyatomic do not use prefixes) • The first thing you should always check for is to see how many elements you have. If you have more than 2 elements, for the purposes of grade 10 science, you will be dealing with polyatomic ions.
Examples • Sodium phosphide • We have a metal (Na+) and a non-metal (P3-). • So we need to balance the equation (Need 3 sodiums to balance out the 3- charge of the P • so the formula becomes Na3P • Dinitrogen pentoxide. • Due to prefixes, this is covalent so the formula is written N2O5. • Titanium (IV) bromate • Titanium (a metal) and bromate (a polyatomic) • Ti4+ and BrO3- • Formula: Ti(BrO3)4