compounds & molecules nacl, salt buckyball, c 60
TRANSCRIPT
Compounds & Compounds & MoleculesMoleculesCompounds & Compounds & MoleculesMolecules
NaCl, saltNaCl, salt
Buckyball, CBuckyball, C6060
Compounds & Compounds & MoleculesMoleculesCompounds & Compounds & MoleculesMolecules
•COMPOUNDSCOMPOUNDS are a combination of 2 are a combination of 2
or more elements in definite ratios by mass. or more elements in definite ratios by mass.
• The character of each element is lost when The character of each element is lost when
forming a compound.forming a compound.
•MOLECULESMOLECULES are the smallest unit of a are the smallest unit of a
compound that retains the characteristics of compound that retains the characteristics of
the compound.the compound.
ELEMENTS THAT EXIST AS ELEMENTS THAT EXIST AS DIATOMICDIATOMIC MOLECULES MOLECULES
ELEMENTS THAT EXIST AS ELEMENTS THAT EXIST AS DIATOMICDIATOMIC MOLECULES MOLECULES
ELEMENTS ELEMENTS THAT EXIST THAT EXIST
AS AS MOLECULESMOLECULES
ELEMENTS ELEMENTS THAT EXIST THAT EXIST
AS AS MOLECULESMOLECULES
Allotropes of CAllotropes of CAllotropes of CAllotropes of C
ELEMENTS THAT EXIST AS ELEMENTS THAT EXIST AS POLYATOMICPOLYATOMIC MOLECULES MOLECULESELEMENTS THAT EXIST AS ELEMENTS THAT EXIST AS POLYATOMICPOLYATOMIC MOLECULES MOLECULES
White P4 and polymeric red phosphorus
S8 sulfur molecules
Molecular CompoundsMolecular CompoundsCompounds without IonsCompounds without Ions
CH4 methane
CO2 Carbon dioxide
BCl3 boron trichloride
MOLECULAR FORMULASMOLECULAR FORMULASMOLECULAR FORMULASMOLECULAR FORMULAS
• Formula for glycine is Formula for glycine is CC22HH55NONO22
• In one molecule there areIn one molecule there are
–2 C atoms2 C atoms
–5 H atoms5 H atoms
–1 N atom1 N atom
–2 O atoms2 O atoms
STRUCTUAL STRUCTUAL FORMULASFORMULASSTRUCTUAL STRUCTUAL FORMULASFORMULAS
• Can also write glycine formula as
–H2NCH2COOHto show atom ordering
• or in the form of a structuralstructural formula formula
C
H
H C
H
H
O
O HN
MOLECULAR MOLECULAR MODELINGMODELING
MOLECULAR MOLECULAR MODELINGMODELING
C
H
H C
H
H
O
O HN
Ball & stickBall & stick Space-fillingSpace-filling
Drawing of glycineDrawing of glycine
Naming Elements & CompoundsNaming Elements & CompoundsChapter 2 & 3: Chemical Equations HandbookChapter 2 & 3: Chemical Equations Handbook
BCl3 boron trichloride
CO2 Carbon dioxide
molecules are formed from two or more nonmetals.
Ionic compounds
have a cation and anion: generally
involve a metal and nonmetal,
NaCl
ammonium ammonium chloride, chloride,
NHNH4ClCl
IONS AND IONIC COMPOUNDSIONS AND IONIC COMPOUNDS
• IONSIONS are atoms or groups of atoms with a positive are atoms or groups of atoms with a positive
or negative charge. or negative charge.
• Taking awayTaking away an electron from an atom gives a an electron from an atom gives a
CATIONCATION with a with a positive chargepositive charge
• AddingAdding an electron to an atom gives an an electron to an atom gives an ANIONANION
with a with a negative chargenegative charge..
Forming Cations & Forming Cations & AnionsAnions
Forming Cations & Forming Cations & AnionsAnions
A A CATIONCATION forms forms when an when an atom atom losesloses one or one or more electrons.more electrons.
An An ANIONANION forms forms when an when an atom atom gainsgains one or one or more electronsmore electrons
Mg --> Mg2+ + 2 e- F + e- --> F-
CATIONCATION + + ANIONANION ---> --->
COMPOUNDCOMPOUND
CATIONCATION + + ANIONANION ---> --->
COMPOUNDCOMPOUND
Are NEUTRAL. Are NEUTRAL. Compounds haveCompounds have
EQUAL number of EQUAL number of ++ and and -- charges. charges.
Are NEUTRAL. Are NEUTRAL. Compounds haveCompounds have
EQUAL number of EQUAL number of ++ and and -- charges. charges.
COMPOUNDCOMPOUNDS FORMED S FORMED FROM IONSFROM IONS
COMPOUNDCOMPOUNDS FORMED S FORMED FROM IONSFROM IONS
NaNa++ + Cl + Cl- - --> NaCl--> NaCl
IONIC COMPOUNDSIONIC COMPOUNDSIONIC COMPOUNDSIONIC COMPOUNDS
NH4+
Cl-
ammonium chloride, NHammonium chloride, NH44ClCl
Properties of Ionic Properties of Ionic CompoundsCompounds
Forming NaCl from Na and ClForming NaCl from Na and Cl22
Properties of Ionic Properties of Ionic CompoundsCompounds
Forming NaCl from Na and ClForming NaCl from Na and Cl22
• A metal atom can A metal atom can transfer an transfer an electron to a electron to a nonmetal.nonmetal.
• The resulting The resulting cation and anion cation and anion are attracted to are attracted to each other by each other by
electrostatelectrostatic forcesic forces..
Electrostatic ForcesElectrostatic Forces
The oppositely charged ions in ionic compounds are The oppositely charged ions in ionic compounds are attracted to one another by attracted to one another by ELECTROSTATIC ELECTROSTATIC FORCESFORCES..
These forces are governed by These forces are governed by COULOMB’S COULOMB’S LAWLAW..
Electrostatic ForcesElectrostatic Forces
COULOMB’S LAWCOULOMB’S LAW
Force of attraction = (charge on +)(charge on -)
(distance between ions)2
DirectDirect relationship between relationship between chargecharge and and forceforce: : charges increase, the force increases.charges increase, the force increases.
InverseInverse relationship between relationship between distancedistance between between ions and ions and forceforce::
increase distance, decrease force.increase distance, decrease force.
Importance of Coulomb’s Importance of Coulomb’s LawLaw
NaCl, NaNaCl, Na++ and Cl and Cl--,,m.p. 804 m.p. 804 ooCC
MgO, MgMgO, Mg2+2+ and O and O2-2-
m.p. 2800 m.p. 2800 ooCC
PREDICTING ION CHARGESPREDICTING ION CHARGESPREDICTING ION CHARGESPREDICTING ION CHARGES
In generalIn general
• metalsmetals (Mg) (Mg) lose electrons lose electrons ---> ---> cationscations
• nonmetalsnonmetals (F) (F) gain electronsgain electrons ---> ---> anionsanions
METALSMETALSM ---> n e- + MM ---> n e- + Mn+n+
where n = periodic groupwhere n = periodic groupNaNa++ sodium ionsodium ionMgMg2+2+ magnesium ionmagnesium ionAlAl3+3+ aluminum ionaluminum ionTransition metals --> MTransition metals --> M2+2+ or M or M3+3+
are commonare commonFeFe2+2+ iron(II) ioniron(II) ionFeFe3+3+ iron(III) ioniron(III) ion
NONMETALSNONMETALSNONMETALSNONMETALS
NONMETAL + n e- ------> XNONMETAL + n e- ------> Xn-n-
where n = 8 - Group no.where n = 8 - Group no.
CC4-4-,carbide,carbide NN3-3-, nitride, nitride OO2-2-, oxide, oxide
SS2-2-, sulfide, sulfide
FF--, fluoride, fluoride
ClCl--, chloride, chloride
Group 7AGroup 6AGroup 4A Group 5A
BrBr--, bromide, bromide
II--, iodide, iodide
Charges on Common Charges on Common IonsIons
Charges on Common Charges on Common IonsIons
+3
-4 -1-2-3+1
+2
By losing or gaining e-, atom has same By losing or gaining e-, atom has same number of e-’s as nearest Group 8A atom.number of e-’s as nearest Group 8A atom.
Binary Ionic Binary Ionic CompoundsCompoundsBinary Ionic Binary Ionic CompoundsCompounds
MnMn2+2+ + O + O2-2- ----> MnO ----> MnO
manganese (II)manganese (II) oxideoxide
AlAl3+3+ + S + S2-2- ----> Al ----> Al22SS33
aluminum sulfidealuminum sulfide
SnSn4+4+ + Cl + Cl-- ----> SnCl ----> SnCl44
Tin (IV) chloride orTin (IV) chloride or
Stannic chlorideStannic chloride calcium fluoridecalcium fluoride
CaCa2+2+ + 2 F + 2 F-- ---> --->
CaFCaF22
Practice Name & Formulas Ultimate Equation Handbook
Only the binary compounds
• Exercise 2-1 pg. 10
• Exercise 3-2 pg 17
Homework:
Worksheets pgs 23-28
POLYATOMIC POLYATOMIC IONSIONS
POLYATOMIC POLYATOMIC IONSIONS
Groups of atoms with a charge.Groups of atoms with a charge.
MEMORIZEMEMORIZE the names and formulas in the names and formulas in
Table 3.1, page 89.Table 3.1, page 89.
Polyatomic IonsPolyatomic IonsPolyatomic IonsPolyatomic Ions
NHNH44++
ammonium ionammonium ion
One of the few common One of the few common polyatomic polyatomic cationscations
Polyatomic IonsPolyatomic IonsPolyatomic IonsPolyatomic Ions
HNOHNO33
nitric acidnitric acid
NONO33--
nitrate ionnitrate ion
Polyatomic Polyatomic IonsIonsPolyatomic Polyatomic IonsIonsCOCO33
2-2-
carbonate ioncarbonate ion
HCOHCO33--
bicarbonate ionbicarbonate ion
hydrogen carbonatehydrogen carbonate
POPO443-3-
phosphate ionphosphate ion
CHCH33COCO22--
acetate ionacetate ion
Polyatomic Polyatomic IonsIons
Polyatomic Polyatomic IonsIons
SOSO442-2-
sulfate ionsulfate ion
SOSO332-2-
sulfite ionsulfite ion
Polyatomic Polyatomic IonsIons
Polyatomic Polyatomic IonsIons
NONO33--
nitrate ionnitrate ion
NONO22--
nitrite ionnitrite ion
Polyatomic Polyatomic IonsIons
Polyatomic Polyatomic IonsIons
Practice Name & Formulas Ultimate Equation Handbook
Add the polyatomic compounds• Exercise 2-1 pg. 10• Exercise 3-2 pg 17• Exercise 4-1 pg 20• Exercise 4-3 pg 21
Homework:Worksheets pgs 23-28 –poly
Pgs 29-33