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Types of BondingTypes of BondingBy: Amanda McArthur and Elysia Dort
Covalent Bonding When two atoms share one or more of their
electrons to form one or more bonding pairs. Conductivity is normally poor. Covalent bonds sometimes form 3- dimensional
covalent networks. Three Dimensional covalent network are made up
of crystal like elements. These can include diamonds, quartz and boron.
Covalent bonds have low melting and boiling points.
Covalent bonds are also split into two other groups. Covalent Polar and Covalent Non-Polar.
Example
This is a perfect example of a Covalent Bond. Hydrogen has one electron and missing one electron from its valence shell. H when bonded with another H share their electron so they can both have a full valence shell. This results in a single bond.
Covalent Polar
Electro negativity difference is 0.5-1.6 Can occur between 2 non-metals, certain
metals and sometimes with both. Shares bonded electrons unequally between
atoms. The element in the bond that is negative is
the one with a higher electro negativity. This one has a stronger “pull” but not strong enough to take the electron for itself. This causes it to have the unequal sharing.
Covalent Polar
Charge is labeled with a sigma with either a positive or negative beside it. It also has an arrow pointed to the atom with the stronger electro negativity.
This example shows the Fluorine has a stronger electro negativity than Hydrogen.
Example- Try This
For each example:a) Draw itb) State the electro negative charge for each
and show the difference.1) HCl2) NaP
Answers
1a)
1b)Cl=3.0, H=2.1 3.0-2.1= 0.9 is the difference.
2a)
2b) Na=0.9, P=2.1 2.1-0.9= 1.2 is the difference.
Covalent Non-Polar
Has an electro negativity difference of 0-0.4
The two or more atoms must both be non-metals.
The electrons are shared equally. Charge is never shown. Their electro negativity must be the same
or close to it so this has a lot of bonding between the same elements.
Example- Try This
1) Draw the following and show the bonds.a)0b)Clc)AsS
Answer
a)
b)
c)
Electron Share Diagram
Starts off looking like the Lewis Dot Diagram by showing how many electrons are in the valence shell.
Then you show what electrons for each atom are being used to bond.
Once that is done you remove the lone pairs or lone electrons. Then for the bonded electrons represent them using a line.
Example- CO
Step one:
Step two:
Step three:
Try ThisDraw the share diagram for a)H 0b) HClc)AlBr
Answers A)
B)
C)
Properties of Ionic CompoundsProperties of Ionic Compounds
Crystalline solidsHigh melting and boiling pointsNormally soluble in waterGood conductors in molten stateVery hard and brittle
Ionic BondingIonic Bonding
Metal + Nonmetal ionic bond
Examples – Classification Metals Examples – Classification Metals and Non-metalsand Non-metals
NaCl Chlorine is a non- metal
Sodium is a metal So NaCl is an ionic compound
CO Oxygen is a non- metal
Carbon is a non-metalSo CO is NOT an ionic bond
Classification of bonds by electro- Classification of bonds by electro- negativitynegativity
You can classify bonds using an electro- negativity chart. (1.7+ is ionic!)
Describes the relative tendencies of the elements to attract electrons during bonding.
You do this by subtracting the electro- negativity of the elements in your compound.
NOTE- these numbers are just approximations and there are exceptions!
Covalent non- polar
Covalent polar
Ionic
0 - 0.4 0.5 – 1.6 1.7 +
Electro-negativity ChartElectro-negativity Chart
Examples Examples NaCl--- Na = 0.9 , Cl = 3.0
so… 3.0 – 0.9 = 2.1 Ionic is 1.7+ So Sodium chloride is Ionic
CO ---- C = 2.5 , O = 3.5so… 3.5 – 2.5 = 1.0 Ionic is 1.7+So Carbon dioxide is NOT ionic.
**HINT- notice that we never multiply the charge of oxygen even though there are 2 oxygen molecules!
Check your understandingCheck your understanding
Are these compounds ionic?(a)Classify using metal and non-metal
method(b) Classify using Electro-negativity
1.MgO2. BeCl
AnswersAnswersMgO--- Mg is a metal, O is a non-metal
Mg = 1.2, O = 3.5 3.5 – 1.2 = 2.3 Magnesium oxide is IONIC
BeCl -- Be is a metal, Cl is a non-metal Be = 1.5, Cl = 3.0 3.0 – 1.5 = 1.5 Beryllium chloride is IONIC
Electron Dot DiagramsElectron Dot DiagramsAlso known as Lewis structuresHelp show the valence electrons present
on an element or compound.Valence electrons- the electrons that are
located on the outermost shell of an element.
They give us a visual image of how ionic bonds works.
Examples- ElementsExamples- Elements
Lithium
Li – 1 dot, 1 valence electron
Phosphorus
P - 5 dots, 5 valence electrons
Electron Dot Diagram ChartElectron Dot Diagram Chart# of valence electrons
1 2 3 4 6 7
Example hydrogen
calcium boron nitrogen sulfur Fluorine
Group 1 2 13 14 16 17
Electron Dot
Diagram H
Ca B
N S F
Check your understandingCheck your understanding
Draw the dot diagrams for the following elements:
Lithium
Aluminum
AnswersAnswersLi--- lithium is in the first group so it has
one valence electron.
Li
Al--- aluminum is in the 13th group so it has 3 valence electrons.
Al
Cations and AnionsCations and AnionsDuring ionic bonding elements either gain
or lose electrons.Cations- elements that lost electrons
during bonding making them positive (+).Anions- elements that gained electrons
during bonding making them negative.(-)Examples: & - cations
& -anions
Electron Dot Diagrams- Electron Dot Diagrams- CompoundsCompounds
Compounds gain or lose electrons to try and form a stable octet.
Octet- a full shell of valence electrons. (Normally 8 except 2 for 1st shell)
Elements do this by trying to form the nearest noble gas.
Ex. Potassium would try to form Argon by losing one electron making the potassium ion.
ExamplesExamplesKI-
K + I the electron moves from K to I giving both potassium and iodine 8 valence electrons.
(K) + ( I ) KI
ExamplesExamplesLi S
Li + Li + S The two lithiums give an electron each giving sulfur a total of 8 electrons and both lithiums eight valance electrons.
(Li) + (Li) + ( S ) Li S
Hydrogen BondingHydrogen BondingHydrogen bonds to very electronegative
atoms (F- 4.0, O- 3.5, N- 3) Example of dipole-dipole forceStronger than normal dipole-dipole forces
weaker than covalent or ionic bonds.Hydrogen is mainly a proton (+)Hydrogen has a strong attraction to negative
parts of other moleculesWhen hydrogen bonds F,O or N it will attract
hydrogen’s electron leaving a unshielded hydrogen.
Hydrogen BondingHydrogen BondingBonded hydrogen naked proton
unshielded + charge greater force to break the bond Higher boiling point
Intermolecular Forces Deals with bonding with neighboring
elements. Has a weak force when compared to
intramolecular forces. Normally the atoms are very close to each
other. There are four kinds of Intermolecular forces.
They include London Forces, Dipole-dipole forces, Dipole-induced dipole forces and Ion-dipole forces.
Examples
Intramolecular Forces Deals with the force of attraction that hold
together atoms to make a molecule or compound.
There are three types of Intramolecular forces. They are Ionic, Covalent and Metallic bonding.
Can occur with metals and non-metals. The electrons are shared except in ionic
bonding which it is held together with electrostatic forces.
Example
Metallic BondingMetallic Bonding metal bonding with the same metal.Electrons move freely (roving sea of
electrons)Forms a lattice structure+ metal and – electron holds the atoms
together
Properties of Metallic BondsProperties of Metallic BondsConduct heat and electricityNormally have high melting
points and boiling pointsStrongMalleableReflect lightDuctile (can be drawn into a wire)
Dipole – dipole forcesDipole – dipole forcesWeak forces that attach the positive end of
one polar molecule with the negative end of another polar molecule.
Stronger than dispersion forces but weaker than hydrogen bonds, ionic or covalent bonds.
Polar and non-polar ends form when one elements do not share electrons equally.
Ex. Here Cl has more of the shared electrons.
Check Your UnderstandingCheck Your UnderstandingWhat types of bonds or forces are present
in the following situations?1.K gives an electron to Cl while bonding
making potassium chloride. 2.Cu bonds to itself making a copper ring.3.Hydrogen an chlorine but chlorine doesn’t
share the electrons equally.4.Frozen water attaches with other frozen
water molecules making ice.
AnswersAnswers
1. Ionic bond2. Metallic bond3. Dipole-dipole forces4. Hydrogen bond/ dipole- dipole forces
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<http://misterguch.brinkster.net/ionic.html>. "Electronegativity." Wikipedia, the Free Encyclopedia. Web. 05
Dec. 2010. <http://en.wikipedia.org/wiki/Electronegativities>. "Properties Of Ionic Compounds | Tutorvista.com." Tutorvista.com
- Online Tutoring, Homework Help for Math, Science, English from Best Online Tutor. Web. 05 Dec. 2010. <http://www.tutorvista.com/content/chemistry/chemistry-iii/chemical-bonding/ionic-compounds.php>.
"Hydrogen Bonds." Edinformatics -- Education for the Information Age. Web. 12 Dec. 2010. <http://www.edinformatics.com/interactive_molecules/hydrogen_bonds.htm>.
"Types of Chemical Bonding." Beyond Books. Web. 12 Dec. 2010. <http://www.beyondbooks.com/psc92/3.asp>.
Therrien, E. Advanced Chemistry 11. Print.
Continued… “Wikipedia” Dec. 5th 2010 http://en.wikipedia.org/wiki/intermolecular_force Wikipedia” Dec. 5th 2010 http://en.wikipedia.org/wiki/intramolecular_force “ “AUS-e-TUTE” copyright: AUS-e-TUTE Dec. 5th 2010 http://
www.ausetute.com.au/intrafor.html “University of Oregon” copy right 2010 University of Oregon Dec 11th 2010
http://darkwing.uoregon.edu/~chem11/L13.htm “Polar vs. Nonpolar” Dec.5th 2010 http://users.stlcc.edu/gkrishnan/polar.html “Chemical Bonding” Copy right 2003-2010 Visionlearing,Inc. Dec.5th 2010 http://
www.visionlearning.com/library/module_viewer.php?mid=55 “Intermolecular Forces” Dec. 11th 2010
www.saskschools.ca/curr_content/chem20/covmolec/interml.html “UNENE Chemistry Primer “ Dec. 11th 2010
www.unene.ca/un-chem-primer/Lectures/Lect_9_Intermol_Forces.ppt.
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