Presentation on theme: "Modern Chemistry Chapter 7 Chemical Formulas & Chemical Compounds"— Presentation transcript:
1 Modern Chemistry Chapter 7 Chemical Formulas & Chemical Compounds
A chemical formula indicates the kind and relative number of atoms in a chemical compound.C8H18 (octane) has 8 carbon and 18 hydrogen atoms.
2 Forming Ionic Compounds
Compounds that have the elements held together by ionic bonds are called ionic compounds.For an ionic compound to exist, the algebraic sum of the positive and the negative charges of the ions MUST = 0.For instance, when a calcium atom becomes an ion, it has an overall 2+ charge which must be neutralized by ion(s) that have a 2- charge.IF a Ca2+ cation forms an ionic bond with an O2- anion, the resulting compound will be neutral and the formula would be CaO.However, if the Ca2+ bonds with a F- anion, it would require two F- ions to neutralize the Ca2+ CaF2
3 Calcium ( Ca2+ ) combines with oxygen ( O2- ) CaO : Ca2+ O2- Calcium (Ca2+ ) combines with fluorine (F1- ) CaF2: F1- Ca F1-
4 Binary Ionic Compounds
monatomic ions- ions formed from a single atomIF the ion has a positive charge, use the name of the elementIF the ion has a negative charge, replace the ending of the element name with “ide”.
5 Binary Ionic Compounds
binary compound- a compound composed of two elementsWriting binary ionic compound formulas:Write the symbols for the ions side by side with the cation being first.IF the charges of the two ions do not add to zero, cross over the charges by using the absolute value of each ion’s charge as the subscript for the other ion so the algebraic sum of the ions equals zero.Check the subscripts and make sure they are in the smallest whole number ratio possible.e.g. aluminum oxide Al3+O Al2O3
6 Naming Binary Ionic Compounds
nomenclature- a naming systemNaming ionic compounds:Write the name of the cation in the formula.Write the name of the anion in the formula.Al2O3 aluminum oxideDo practice problems #1 & 2 on page 223.
7 Problems- page 223 a- potassium (K+) & iodide (I-) KI
b- magnesium (Mg2+) & chloride (Cl-) MgCl2c- sodium (Na+) & sulfide (S2-) Na2Sd- aluminum (Al3+) & sulfide (S2-) Al2S3e- aluminum (Al3+) & nitride (N3-) AlN
8 #2 a) AgCl silver chlorideb) ZnO zinc oxidec) CaBr2 calcium bromided) SrF2 strontium fluoridee) BaO barium oxidef) CaCl2 calcium chloride
9 Stock System of Nomenclature
Some metallic elements that form cations such as chromium, cobalt, copper, iron, lead, manganese, mercury, nickel, and tin can form cations of more than one charge. (See ion chart)For cations that can have multiple ionic charges, place a Roman numeral in parentheses that is equal to the ionic charge after the name of the metal.Cu1+ copper (I) Fe2+ iron (II)Cu2+ copper (II) Fe3+ iron (III)
10 Using the Stock System Write the formula of the ionic compound.
Use the charge of the anion to determine the charge of the cation.Write the name of the cation with the charge followed by the name of the anion.CuCl copper (I) chlorideCuCl2 copper (II) chlorideDo practice problems #1 & 2 on page 225.
11 Practice- page 225 CuBr2 copper II bromide b) Fe 2+ & O2-
#1 a) Cu2+ & Br- CuBr2 copper II bromideb) Fe 2+ & O2- FeO iron II oxidec) Pb 2+ & Cl- PbCl2 lead II chlorided) Hg 2+ & S2- HgS mercury II sulfidee) Sn 2+ & F- SnF2 tin II fluoridef) Fe 3+ & O2- Fe2O3 iron III oxide
12 Practice- page 225#2 a) CuO copper II oxideb) CoF3 cobalt III fluoridec) SnI4 tin IV iodided) FeS iron II sulfide
13 Polyatomic Ionspolyatomic ion- a group of covalently bonded atoms with an ionic chargeoxyanion- a negatively charged polyatomic ion that contains oxygen
14 Ionic Compounds & Polyatomic Ions
Writing and naming strategies are the same for ionic compounds with polyatomic ions. However, if more than one polyatomic ion is needed in the formula, the formula of the polyatomic ion is placed in parentheses and a subscript is used outside the parenthesis to show how many of the polyatomic ions are needed.e.g iron (II) nitrate Fe(NO3)2Do practice problems #1 & 2 on page 227.
15 Practice Problems #1 page 227
a- sodium iodideNaIb- calcium chlorideCaCl2c- potassium sulfideK2Sd- lithium nitrateLiNO3
16 e- copper (II) sulfateCuSO4f- sodium carbonateNa2CO3g- calcium nitriteCa(NO2)2h- potassium perchlorate KClO4
17 2a- Ag2Osilver oxideb- Ca(OH)2calcium hydroxidec- KClO3potassium chlorated- NH4OHammonium hydroxidee- Fe2(CrO4)3iron (III) chromatef- KClOpotassium hypochlorite
18 Practice Do the following formulas match the names given?
IF they do not match, provide the CORRECT name or formula.CuSO4 copper I sulfateFe2(SO4)3 iron III sulfateFeSO4 iron II sulfatecopper I nitrate CuNO3copper II nitrate Cu2NO3
19 Practice CuSO4 copper I sulfate NO [copperII]
Do the following formulas match the names given?CuSO4 copper I sulfateNO [copperII]Fe2(SO4)3 iron III sulfateYESFeSO4 iron II sulfatecopper I nitrate CuNO3copper II nitrate Cu2NO3NO [Cu(NO3)2]
20 Ionic Compound Nomenclature
Name the following compounds:MgBr2CuOCu2OFeSO4Fe2(SO4)3CaSO4Cu2SO4CuSO4FePO4Fe3(PO4)2
21 Ionic Compound Nomenclature
Name the following compounds:MgBr2magnesium bromideCuOcopper II oxideCu2Ocopper I oxideFeSO4iron II sulfateFe2(SO4)3iron III sulfate
22 CaSO4calcium sulfateCu2SO4copper I sulfateCuSO4copper II sulfateFePO4iron III phosphateFe3(PO4)2iron II phosphate
23 Ionic Compound Nomenclature
Write the formulas of the following ionic compounds:aluminum nitratealuminum nitridemagnesium phosphatemagnesium bromidecopper I sulfatecopper II sulfateiron II nitrateiron III fluoridecalcium hydroxidecalcium phosphate
24 aluminum nitrate Al 3+ NO3 1- Al(NO3)3 aluminum nitride Al 3+ N 3- AlN magnesium phosphate Mg 2+ PO4 3- Mg3(PO4)2
25 magnesium bromide Mg 2+ Br 1- MgBr2 copper I sulfate Cu 1+ SO4 2- Cu2SO4 copper II sulfate Cu 2+ SO4 2- CuSO4 iron II nitrate Fe 2+ NO3 1- Fe(NO3)2
26 iron III fluoride Fe 3+ F 1- FeF3 calcium hydroxide Ca 2+ OH 1- Ca(OH)2 calcium phosphate Ca 2+ PO4 3- Ca3(PO4)2
27 Binary Molecular Compounds
For this course, molecular compounds consist of two non-metals. For our purposes, hydrogen will be considered a non-metal.The ratio of the elements is NOT determined by their individual ionic charges.e.g. CO & CO2 or H2O & H2O2
28 Naming of Binary Molecular Compounds From Formulas
Write the name of the first element in the formula.Write the name of the second element using the suffix “ide”.Use numerical prefixes to show the number of atoms of each element.e.g. P2O5 diphosphorus pentoxide1 = mono 6 = hexa2 = di 7 = hepta3 = tri 8 = octa4 = tetra 9 = nona5 = penta = deca
29 Binary Molecular Compounds
P4O10 tetra + phosphorus & dec + oxidetetraphosphorus decoxideCO carbon & mon + oxidecarbon monoxideCO2 carbon & di + oxidecarbon dioxide
30 Formulas for Molecular Compounds
The element with the smaller group number is usually given first. If both elements are in the same group, the element with the larger period number is given first. This element is given a prefix ONLY if it contributes more than one atom to the molecule of the compound.The second element is named by combining a prefix for the number of atoms of the element in the compound, the root of the name of the element, and the suffix “ide”.The “o” or the “a” at the end of a prefix is usually dropped when the word following the prefix begins with another vowel.
31 Writing Molecular Formulas
Write the formula of the first element in the compound name followed by the numerical subscript that shows how many there are (if there is no numerical prefix, there is one atom of the element).Write the formula of the second element in the compound name followed by a subscript that shows how many atoms of the element are designated by the numerical prefix in the name.carbon dioxide CO2Do practice problems #1 & 2 on page 229.
32 Practice Problems #1 & 2 page 229
1- a- SO3sulfur trioxideb- ICl3iodine trichloridec- PBr5phosphorus pentabromide2- a- carbon tetraiodideCI4b- phosphorus trichloridePCl3c- dinitrogen trioxideN2O3
33 Molecular Compound Nomenclature
Name the following molecular compounds.N2O5SO2P4O10COCO2SiO2H2O2CF4PBr3SF2
34 Name the following molecular compounds.
N2O5 dinitrogen pentoxideSO2 sulfur dioxideP4O10 tetraphosphorus decoxideCO carbon monoxideCO2 carbon dioxideSiO2 silicon dioxideH2O2 dihydrogen dioxideCF4 carbon tetrafluoridePBr3 phosphorus tribromideSF2 sulfur difluoride
35 Molecular Compound Nomenclature
Write the formula for the following compounds.carbon tetraiodidetrinitrogen heptoxidetriphosphorus hexasulfideoxygen dichloridedisilicon triphosphidetetranitrogen heptoxidecarbon disulfidedihydrogen monosulfidetrihydrogen monophosphidesilicon disulfide
36 Molecular Compound Nomenclature
Write the formula for the following compounds.carbon tetraiodide CI4trinitrogen heptoxide N3O7triphosphorus hexasulfide P3S6oxygen dichloride OCl2disilicon triphosphide Si2P3tetranitrogen heptoxide N4O7carbon disulfide CS2dihydrogen monosulfide H2Strihydrogen monophosphide H3Psilicon disulfide SiS2
37 Section Review Problem #2 page 231
2- a- aluminum + bromine AlBr3b- sodium + oxygen Na2Oc- magnesium + iodine MgI2d- lead (II) + oxygen PbOe- tin (II) + iodine SnI2f- iron (III) + sulfur Fe2S3g- copper (II) + nitrate Cu(NO3)2h- ammonium + sulfate (NH4)2SO4
38 Section Review Problem #3 page 231
a- NaI sodium iodideb- MgS magnesium sulfidec- CaO calcium oxided- K2S potassium sulfidee- CuBr copper (I) bromidef- FeCl2 iron (II) chloride
39 Section Review Problem #4 (a-e) page 231
a- sodium hydroxide NaOHb- lead (II) nitrate Pb(NO3)2c- iron (II) sulfate FeSO4d- diphosphorus trioxide P2O3e- carbon diselenide CSe2
40 Oxidation Numbersoxidation numbers (oxidation states)- assigned to the atoms composing a molecular compound or polyatomic ion that indicate the general distribution of electrons among the bonded atoms in the compound or ion
41 Assigning Oxidation Numbers
The atoms in a pure element are assigned an oxidation number of zero.The more electronegative (second) element in a binary molecular compound is assigned the number equal to the negative charge it would have if it were an anion.Fluorine always has an oxidation number of -1 because it is the most electronegative element.Oxygen has an oxidation number of -2 in almost all compounds.
42 5) Hydrogen has an oxidation number of +1 in compounds where it is listed first and -1 when it is listed last in the compound formula.6) The algebraic sum of all oxidation numbers in a neutral compound is equal to zero.7) The algebraic sum of the oxidation numbers of the atoms in a polyatomic ion equal the ion’s charge.8) Oxidation numbers can also be assigned to atoms in an ionic compound.
43 Using Oxidation Numbers
Do practice problem #1 on page 234.
44 Practice #1 pg 234a) HCl H = 1+ Cl = 1-b) CF4 C = 4+ F = 1-c) PCl3 P = 3+ Cl = 1-d) SO2 S = 4+ O = 2-e) HNO3 H = 1+ N = 5+ O = 2-f) KH K = 1+ H = 1-g) P4O10 P= 5+ O = 2-h) HClO3 H = 1+ Cl = 5+ O = 2-i) N2O5 N = 5+ O = 2-j) GeCl2 Ge = 2+ Cl = 1-
45 Oxidation Number problems
What would be the oxidation number of each element in the following compounds & polyatomic ions?H2O H = O =H2SO4 H = S = O =N2O5 N = O =SO42- S = O =PO43- P = O =
46 H = 1+ O = 2- H2SO4 H = 1+ S = 6+ O = 2- N2O5 N = 5+ O = 2- SO42-
What would be the oxidation number of each element in the following compounds & polyatomic ions?H2OH = 1+ O = 2-H2SO4H = 1+ S = 6+ O = 2-N2O5N = 5+ O = 2-SO42-S = 6+ O = 2-PO43-P = 5+ O = 2-
47 Oxidation Numbers & the Stock System
We can use oxidation numbers assigned to the less electronegative (first) element to name binary molecular compounds by using the oxidation number as if it were a cation.PCl3 phosphorus trichloride phosphorus (III) chlorideDo section review problems #1-2 on page 235.
48 Problems page 235#1a- HFH = 1+ F = 1-b- CI4C = 4+ I = 1-c- H2OH = 1+ O = 2-d- PI3P = 3+ I = 1-e- CS2 C = 4+ S = 2-f- This is a rare case when O = 1-.g- H2CO3 H = 1+ C = 4+ O = 2-h- NO21- N = 3+ O = 2-
49 Problems page 235#2a- CI4 carbon (IV) iodideb- SO3 sulfur (VI) oxidec- As2S3 arsenic (III) sulfided- NCl3 nitrogen (III) chloride
50 Oxidation Numbers & the Stock System
Using oxidation numbers & the stock system, what would be the names of the following binary molecular compounds? (fill in the blank with the roman numeral)N2O5 nitrogen __ oxideSiO2 silicon __ oxideCF4 carbon __ fluoridePI3 phosphorus __ iodideSiBr4 silicon __ bromide
51 nitrogen V oxide SiO2 silicon IV oxide CF4 carbon IV fluoride
Using oxidation numbers & the stock system, what would be the names of the following binary molecular compounds?N2O nitrogen V oxideSiO silicon IV oxideCF carbon IV fluoridePI phosphorus III iodideSiBr4 silicon IV bromide
52 Chapter 7 part 1 worksheet
Write the formula for the following ionic compounds.1- magnesium phosphateMg3(PO4)22- calcium hydroxideCa(OH)23- iron (II) nitrateFe(NO3)24- iron (III) sulfateFe2(SO4)35- ammonium carbonate(NH4)2CO3
53 6- FeSO4 iron (II) sulfate 7- FePO4 iron (III) phosphate 8- KNO3
Write the name of the following ionic compounds.6- FeSO4iron (II) sulfate7- FePO4iron (III) phosphate8- KNO3potassium nitrate9- CuSO4copper (II) sulfate10- Cu2SO4copper (I) sulfate
54 11- dinitrogen pentoxide N2O5 12- triphosphorus heptasulfide P3S7
Write the formula of the following molecular compounds.11- dinitrogen pentoxideN2O512- triphosphorus heptasulfideP3S713- silicon dioxideSiO214- carbon tetrachlorideCCl415- disulfur trioxideS2O3
55 Write the name of the following molecular compounds using numerical prefixes.
16- H2O2dihydrogen dioxide17- P2O6diphosphorus hexoxide18- SiS2silicon disulfide19- N4O10tetranitrogen decoxide20- PI3phosphorus triiodide
56 Write the name of the following molecular compounds using the Stock system. 21- H2O hydrogen (I) oxide 22- P2O5 phosphorus (V) oxide 23- SiS2 silicon (IV) sulfide 24- N4O10 nitrogen (V) oxide 25- PI3 phosphorus (III) iodide
57 Determine the oxidation numbers assigned to each element in the following compounds or ions.
26- N2O5N = 5+ O = 2-27- CO2C = 4+ O = 2-28- SO3S = 6+ O = 2-
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