Ch 7 PowerPoint Notes Ch 7 PowerPoint Notes
Section 7.1 - IonsSection 7.1 - Ions
OBJECTIVES:OBJECTIVES:
Determine the number Determine the number of of valence electronsvalence electrons in in an atom of a an atom of a representative element.representative element.
Section 7.1 - IonsSection 7.1 - Ions
OBJECTIVES:OBJECTIVES:
Explain how the octet Explain how the octet rule applies to atoms of rule applies to atoms of metallic and nonmetallic metallic and nonmetallic elements.elements.
Section 7.1 - IonsSection 7.1 - Ions
OBJECTIVES:OBJECTIVES:
Describe how Describe how cationscations and anions form.and anions form.
Why do some elements react to Why do some elements react to form compounds and others do not?form compounds and others do not?
Is there any way to predict if atoms Is there any way to predict if atoms might react with each other?might react with each other?
Is there any way to predict what Is there any way to predict what chemical formulas might be formed?chemical formulas might be formed?
Ionic and Metallic BondingIonic and Metallic Bonding
Na 1+, Na +1 or Na+ = cation , missing 1 e-
O2- = anion, gained 2 e-
(the number is the charge on ion, not # of e- gained or lost,, i.e., +1 means 1 electron lost, not 1 gained.)
Ion definitionsIon definitionsValence electronsValence electrons: Outermost electrons. The : Outermost electrons. The
ss and and pp electrons in the outer energy level. electrons in the outer energy level. The highest occupied energy level.The highest occupied energy level.
Core electronsCore electrons:: are those in the energy levels are those in the energy levels below.below.
IonIon:: An atom that has lost or gained an electron. An atom that has lost or gained an electron. Ions have a + or - charge. Ions have a + or - charge.
(Atoms are always neutral, # of p+ = # of e(Atoms are always neutral, # of p+ = # of e--)) CationCation:: Positive Ion or metals, gained e Positive Ion or metals, gained e--.. AnionAnion:: Negative Ion or non-metals, Lost e Negative Ion or non-metals, Lost e--..
Valence Electrons are…?Valence Electrons are…?The electrons responsible for the The electrons responsible for the
chemical properties of atoms, and chemical properties of atoms, and are those in the are those in the outerouter energy level. energy level.
Valence electronsValence electrons - The - The ss and and pp electrons in the outer energy levelelectrons in the outer energy levelthe highest occupied energy levelthe highest occupied energy level
Core electronsCore electrons – are those in the – are those in the energy levels below.energy levels below.
Keeping Track of ElectronsKeeping Track of Electrons Atoms in the same column (group)...Atoms in the same column (group)...
1)1) Have the same outer electron Have the same outer electron configuration.configuration.
2)2) Have the same valence electrons.Have the same valence electrons. The number of valence electrons are The number of valence electrons are
easily determined. It is the easily determined. It is the group group numbernumber for representative. for representative.
Group 2A: Be, Mg, Ca, etc.Group 2A: Be, Mg, Ca, etc. have 2 valence electronshave 2 valence electrons
Group 8A, Noble gases has 8.Group 8A, Noble gases has 8.
Electron Dot diagrams Electron Dot diagrams are…are… DEF: Shows the 8 valence electrons as dot DEF: Shows the 8 valence electrons as dot
pairs around the chemical symbol.pairs around the chemical symbol. A way of showing & keeping track A way of showing & keeping track
of valence electrons.of valence electrons. How to write them?How to write them? Write the symbol - it represents the nucleus Write the symbol - it represents the nucleus
and inner (core) electronsand inner (core) electrons Put one dot for each valence electron (Put one dot for each valence electron (8 8
maximummaximum)) They don’t pair up until they have to (Hund’s They don’t pair up until they have to (Hund’s
rule). Do 4 singles before pairs.rule). Do 4 singles before pairs.
X
Electron Dot diagramsElectron Dot diagramsSingle dots can be on any side.Single dots can be on any side.
1A 2A 3A 4A
5A 6A 7A 8A
Valence e- Valence e- highest electron highest electron energy level of an atomenergy level of an atom
((nns s nnp…where n is the same numberp…where n is the same number))
Nitrogen 1sNitrogen 1s22 2s2s22 2p 2p33 5 Valence e- 5 Valence e-
e- dot structures show only e- dot structures show only valence e-valence e-
(single per side/then pair up)(single per side/then pair up)2 dots Mg –[Ne]3s2 dots Mg –[Ne]3s22 3p 3p0 0
Need to Memorize!! EASY!Need to Memorize!! EASY!
valence e-valence e- determine the determine the chemical properties of an chemical properties of an
elementelement
Alkali metals (1 ve-) - Alkali metals (1 ve-) - nnss11 nnpp0 0
Remember s, p, d, f blocksRemember s, p, d, f blocks
1234567
1234567
S p1S1 1S2
2S1 2S2
3S1 3S2
2p1 2p2 2p32p4 2p5 2p6
Write the e dot structuresWrite the e dot structures O = 1sO = 1s22 2s2s22 2p 2p44
Ne = Ne = Na = Na =
Write the e dot structuresWrite the e dot structures
O = 1sO = 1s22 2s2s22 2p 2p44
Ne = 1sNe = 1s22 2s2s22 2p 2p66
Na = 1sNa = 1s22 2s 2s22 2p 2p66 3s3s11 3p 3p
e dot structures – show valence e dot structures – show valence e- as dotse- as dots
O = 1sO = 1s22 2s2s22 2p 2p44
Ne = 1sNe = 1s22 2s2s22 2p 2p66
Na = 1sNa = 1s22 2s 2s22 2p 2p66 3s3s11 3p 3p
octet rule – ions tend to have octet rule – ions tend to have pseudo noble gas configuration pseudo noble gas configuration
(8 valence e-)(8 valence e-)full s and p orbitals full s and p orbitals
Formation of CationsFormation of CationsMetals Metals loselose electrons electrons to attain a noble to attain a noble
gas configuration.gas configuration.They make positive ions They make positive ions (cations)(cations)If we look at the electron configuration, If we look at the electron configuration,
it makes sense to lose electrons:it makes sense to lose electrons:Na Na 1s1s222s2s222p2p663s3s11 1 valence electron 1 valence electronNaNa1+1+ 1s1s222s2s222p2p66 This is a noble gas This is a noble gas
configuration with 8 electrons in the configuration with 8 electrons in the outer level.outer level.
Electron Dots For CationsElectron Dots For CationsMetals will have few valence electrons Metals will have few valence electrons
(usually 3 or less); calcium has only 2 (usually 3 or less); calcium has only 2 valence electronsvalence electrons
Ca
Electron Dots For CationsElectron Dots For CationsMetals will have few valence electronsMetals will have few valence electronsMetals will Metals will lose the valence electronslose the valence electrons
Ca
Electron Dots For CationsElectron Dots For CationsMetals will have few valence electronsMetals will have few valence electronsMetals will Metals will lose the valence electronslose the valence electronsForming positive ionsForming positive ions
Ca2+NO DOTS are now shown for the cation.
This is named the “calcium ion”.
Electron Configurations: Electron Configurations: AnionsAnionsNonmetals Nonmetals gaingain electrons electrons to attain to attain
noble gas configuration.noble gas configuration.They make negative ions They make negative ions (anions)(anions)SS = = 1s1s222s2s222p2p663s3s223p3p44 = 6 valence = 6 valence
electronselectronsSS2-2- = = 1s1s222s2s222p2p663s3s223p3p66 = noble gas = noble gas
configuration. configuration. Halide ionsHalide ions are ions from chlorine or are ions from chlorine or
other halogens that gain electronsother halogens that gain electrons
Electron Dots For AnionsElectron Dots For AnionsNonmetals will have many valence Nonmetals will have many valence
electrons (usually 5 or more)electrons (usually 5 or more)They will They will gaingain electrons to fill outer shell. electrons to fill outer shell.
P 3-(This is called the “phosphide ion”, and should show dots)
Stable Electron ConfigurationsStable Electron Configurations All atoms react to try and achieve a All atoms react to try and achieve a
noble gas configuration.noble gas configuration. Noble gases have 2 s and 6 p electrons.Noble gases have 2 s and 6 p electrons. 8 valence electrons = already stable!8 valence electrons = already stable! This is the This is the octet ruleoctet rule (8 in the outer level (8 in the outer level
is particularly stable).is particularly stable).
Ar
ATOMATOMNa = 1sNa = 1s22 2s 2s22 2p 2p66 3s3s11 3p 3p00
IONIONNaNa+1+1 = 1s = 1s22 2s2s22 2p 2p66
a. What is the charge of an e-?a. What is the charge of an e-?
b. What is the e- config for N b. What is the e- config for N 3-3- ion? ion?
c. How many e- does (B) have?c. How many e- does (B) have?
d. how many valence e- does (B) have?d. how many valence e- does (B) have?
Common IONIC CHARGES Common IONIC CHARGES OF OF REPRESENTATIVE ELEMENTSREPRESENTATIVE ELEMENTSAdd to periodic tableAdd to periodic table
11+1+1
2 2 +2+2
1313+3+3
1414 1515-3-3
16 16 -2-2
17 17 -1-1
Li Li NaNaKK
RbRbCsCs
Be Be MgMgCaCaSrSrBaBa
AlAl
N N PPAsAs
O O SS
SeSe
F F ClClBrBrII
Why don’t the noble gases form Why don’t the noble gases form ions?ions?
When writing SWhen writing S2-2-, what does , what does the 2- indicate?the 2- indicate?
Does this ion have more or Does this ion have more or less e than the original atom?less e than the original atom?
Section 7.2 Ionic Bonds and Section 7.2 Ionic Bonds and Ionic CompoundsIonic Compounds
OBJECTIVES:OBJECTIVES:
ExplainExplain the electrical the electrical charge of an ionic charge of an ionic compound.compound.
Section 7.2 Ionic Bonds and Section 7.2 Ionic Bonds and Ionic CompoundsIonic Compounds
OBJECTIVES:OBJECTIVES:
DescribeDescribe three three properties of ionic properties of ionic compounds.compounds.
Ionic Compounds – Ionic Compounds – compounds formed from compounds formed from
cations and anionscations and anions Usually a metal and a Usually a metal and a
nonmetal nonmetal (the charges always cancel)(the charges always cancel)
NaNa++, Cl, Cl-- = NaCl = NaCl
Ionic BondingIonic BondingAnions and cations are held together Anions and cations are held together
by by opposite chargesopposite charges (+ and -) (+ and -)Ionic compounds are called Ionic compounds are called saltssalts..Simplest Simplest ratioratio of elements in an ionic of elements in an ionic
compound is called the compound is called the formula unitformula unit..The bond is formed through the The bond is formed through the
transfer of electrons (lose and gain)transfer of electrons (lose and gain)Electrons are transferred Electrons are transferred to achieve to achieve
noble gas configuration (Octet Rule).noble gas configuration (Octet Rule).
Ionic CompoundsIonic Compounds
1)1) Also called Also called SALTSSALTS
2)2) Made from: a Made from: a CATIONCATION with an with an ANIONANION (or literally (or literally from a from a metalmetal combining combining with a with a nonmetalnonmetal))
Ionic BondingIonic Bonding
Na ClThe metal (sodium) tends to lose its one electron from the outer level.
The nonmetal (chlorine) needs to gain one more to fill its outer level, and will accept the one electron that sodium is going to lose.
Ionic BondingIonic Bonding
Na+ Cl -
Note: Remember that NO DOTS are now shown for the cation!
Chemical formula Chemical formula = number of = number of atoms in a atoms in a
formula unitformula unit of an of an ionic compound ionic compound (and not the charges (and not the charges
on the ions)on the ions)
Formula unit = Formula unit = NaClNaCl
Ionic BondingIonic Bonding
All the electrons must be accounted forAll the electrons must be accounted for, , and and eacheach atom will have a noble gas atom will have a noble gas configuration (which is stable).configuration (which is stable).
Ca P
Lets do an example by combining calcium and phosphorus:
Ionic BondingIonic Bonding
Ca P
Ionic BondingIonic Bonding
Ca2+ P
Ionic Bonding
Ca2+ P
Ca
Ionic Bonding
Ca2+ P 3-
Ca
Ionic Bonding
Ca2+ P 3-
Ca P
Ionic Bonding
Ca2+ P 3-
Ca2+ P
Ionic Bonding
Ca2+ P 3-
Ca2+ P
Ca
Ionic Bonding
Ca2+ P 3-
Ca2+ P
Ca
Ionic Bonding
Ca2+ P 3-
Ca2+P
3-
Ca2+
Ionic Bonding
= Ca3P2Formula Unit
This is a chemical formula, which shows the kinds and numbers of atoms in the smallest representative particle of the substance.
For an ionic compound, the smallest representative particle is called a: Formula Unit
Chemical formula Chemical formula = number of = number of atoms in a atoms in a
formula unitformula unit of an of an ionic compound ionic compound (and not the charges (and not the charges
on the ions)on the ions)
Formula unit = Formula unit = NaClNaCl
Ionic compounds are Ionic compounds are usually brittle solids usually brittle solids
at room temperature, at room temperature, with repeating with repeating
internal 3-D crystal internal 3-D crystal patterns, that have patterns, that have high melting pointshigh melting points
Ionic bonds – electrostatic Ionic bonds – electrostatic force that holds compound force that holds compound
togethertogether
What number of each ion do What number of each ion do you need to make an ionic you need to make an ionic compound?compound?
Na, FNa, F
Na, SNa, S
Al, NAl, N
What number of each ion do What number of each ion do you need to make an ionic you need to make an ionic compound?compound?
Na, FNa, F NaFNaF Na, SNa, S NaNa22SS
Al, NAl, N AlNAlN
Metal bonds Metal bonds
valence electrons of metal atoms valence electrons of metal atoms can be modeled as a sea of can be modeled as a sea of
electrons electrons Metallic bonds Metallic bonds = free-floating = free-floating
valence electrons attracted to the valence electrons attracted to the positively charged metal ionspositively charged metal ions
Alloys Alloys are mixtures composed of are mixtures composed of two or more elements, at leasttwo or more elements, at least
one of which is a metalone of which is a metal
Quick review questionsQuick review questions Can have everyone stand up and answers following q’s to sit down.Can have everyone stand up and answers following q’s to sit down.
An ionic compound is usually An ionic compound is usually formed between a metal and a formed between a metal and a
__?__?
How many dots around a sodium How many dots around a sodium atom?atom?
How many dots around a sodium How many dots around a sodium atom?atom?
What is the charge on a sodium What is the charge on a sodium atom?atom?
What is the charge on a sodium What is the charge on a sodium ion?ion?
What are some ionic compounds What are some ionic compounds formed with sodium?formed with sodium?
What is the charge on an aluminum What is the charge on an aluminum ion?ion?
What are some ionic compounds What are some ionic compounds formed with Aluminum?formed with Aluminum?