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Unit 4 . Inorganic Nomenclature. Metals: Form positive ions. Non-metals: Form negative ions. (H is the exception). Anion: negatively charged ion ( Cl - , O 2 - , NO 3 - ). Cation positively charged ion (K + , Al 3+ , NH 4 + ). Monatomic: only one atom (Ne, Na+, I-).
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Unit 4 Inorganic Nomenclature
Metals: Form positive ions. Non-metals: Form negative ions. (H is the exception). • Anion: negatively charged ion (Cl-, O2-, NO3-). • Cation positively charged ion (K+, Al3+, NH4+). • Monatomic: only one atom (Ne, Na+, I-). • Diatomic: two atoms (O2, NaCl, I2, LiBr). • Triatomic: three atoms (K2S, O3, H2O). • Polyatomic: many atoms. (Poly means more than one). (CH4, C2H6O, NaCl) Metals vs Non-Metals
a) Naming Monatomic ions • monatomic metal ions: Place the word ion after the name of the metal. eg. Potassium metal (K) forms the potassium ion (K+). (monatomic metal ions will have a charge) • monatomic metal ions with more than one possible combining #: • place the roman numeral charge value in brackets between the metal name and the word ion. • eg. Fe3+ = Iron (III) ion, • Fe2+= Iron (II) ion, • Cu3+ = Copper (III) ion. Naming Inorganic Particles
2) Naming monatomic non-metal ions: • Change the ending of the non-metal to “ide”.(means negative charge.)
b) Naming Polyatomic ions • Polyatomic ions are compounds that carry a charge.
An Ionic Compound is a compound made of ions. The 3 Formula Rules: • Put down the symbols of the ions. • Add brackets around any complex ion. • Write the positive (metallic) ion first. • e.g. Ca Cl or Ca(OH) 2. Put combining numbers above each symbol. e.g. Ca 2+ Cl 1- or Ca 2+ (OH) 1- Finding Formulas of Ionic Compounds 3. cross out the positive and negative signs criss-cross the combining numbers and use them as subscripts. eg. Ca+2 +Cl-1Ca1Cl2 = CaCl2 or Ca(OH)2
If the subscript is “one”, you don’t need to write it. (Na1Cl1 = NaCl) • You must reduce subscripts if possible. Is there a number that will divide evenly into both subscripts? (i.e. Mg2O2 = MgO) • Subscripts inside brackets of complex ions must NOT be changed • eg. Ca2+ + NO3 1-Ca(NO3)2 • If the subscript outside brackets is one, don’t write the brackets • eg. Na(OH)1NaOH Notes:
Lead (IV) Oxide: Pb+4 O-2Pb2O4 = PbO2 Lead (II) Oxide: Pb+2O-2Pb2O2 = PbO More Than One Combining Capacity
magnesium and oxygen__ • Mg2O2 MgO • 2. potassium and sulphate___________ • K2SO4 • 3. hydrogen and fluorine___________ • HF • 4. calcium and hydrogen____________ • CaH2 Try these examples on your own:
A. Binary Compounds / Only two elements /a metal and a non-metal To name: a) Name the metal first without changing its name b) Name the non-metal second and change its ending to ide E.g. BeBr2 = Beryllium bromide Naming Ionic Compounds
Sodium and Bromine________________ __________________ Potassium and Oxygen______________ ______________________ Write the formula, then the name:
Sodium and Bromine____________ NaBr __Sodium Bromide___________ Potassium and Oxygen__________ K2O __Potassium Oxide___ Write the formula, then the name:
-Some elements can have multiple charges/comb. #s -Use Roman numerals to specify which ion it is: Eg Fe(II) = Fe 2+ Look at the periodic table Fe(III) = Fe 3+ see more than one comb cap To name: a) find combining # by reverse criss-cross b) change combining # to roman numeral, put after metal name B. Compounds containingelements with more than one combining capacity *Only metals can form more than one possible type of ion* E.g. FeCl2 = Fe 2+ and Cl1- = _Iron (II) Chloride_____________________
Iron (II) and Oxygen _________ FeO __Iron (II) Oxide___ • Copper (I) and Bromine ______ CuBr _Copper (I) Bromide Write the formula, then the name:
To name: Refer to your Periodic Table of Common Ions Put: 1. positive ion first. 2. negative ion second. Charged Groups of Atoms (Polyatomic Ions) E.g. Ba 2+ + SO42- = BaSO4 = Barium sulphate E.g. Ba 2+ + PO43- = Ba3(PO4)2 = Barium phosphate
Potassium and Bicarbonate _________ KHCO3__ Potassium Bicarbonate _ Magnesium and Nitrate _______ Mg(NO3)2__ __Magnesium Nitrate Write the formula, then the name:
Class work: p. 71 – 72 • #4. a – o • #5. a – o
Crystals of ionic compounds often have water “stuck” to them. eg. when Copper (II) Sulphate is crystallized from a water solution, the resulting crystals have the formula: CuSO4· 5H2O 5 water molecules are attached to every CuSO4 Naming Hydrates the waters attached are called “Hydrates” prefixes are used to tell the number of Hydrates attached
Hydrate name = compound name + prefix + “hydrate” eg. name of CuSO4· 5H2O = “copper (II) sulfate pentahydrate” Ca(NO3)2· 4H2O = “calcium nitrate tetrahydrate” Homework: p. 73 #6. a,c,e,g,i #7. a,c,e,
usually are covalently bonded molecules • composed of two different types of atoms • it is assumed one particle is cation-like and the other is anion-like Naming Binary Compounds
Use prefix system (mono, di, tri, …) 2. Cation-like element written 1st, anion-like element written 2nd 3. Ending of name changed to “ide” Naming Binary Compounds: eg.CO = Carbon monoxide.
4. Place prefix, according to the number of that atom within the molecule, in front of the elements’ name So P2S3 is written: “Diphosphorus trisulphide” ****exception: if only one atom in cationic spot, then do not place the prefix mono in front of the elementalname. eg. NO2 = Nitrogen dioxide, not mononitrogen dioxide. What about P2S3?
NCl3 = Nitrogen trichloride. • P4O6 = Tetraphosphorus hexaoxide. • S2F2 = Disulphur difluoride. • NI3 = Nitrogen triiodide. • ICl = Iodine monochloride. Practice:
Homework p. 74 #8 a,c,e,g • #9 a,c,e,g,i
An acid is a compound starting with an H (hydrogen), and has a pH < 7. Most acids contain: oxygen, hydrogen a non-metal. When dissolved in water, an acid breaks apart: acid “anion” + H+ Naming Common Acids eg: HNO2 + water → NO2- + H+ acid anion