Structure Bonding And Properties
MetallicIonicStructure and Properties of SolidsNetworkCovalent
Structure and Properties of SolidsWe need to use: ionic, covalent and metallic bondingand molecular, ionic, metallic and covalent network structureTo explain properties of substances: melting and boiling points, solubility, electrical conductivity,malleability, ductility, and hardness.
PropertiesWhat determines the:melting point of a compoundhow strong the bonds are that hold the compoundtogether – the stronger the bond the more energyrequired to break itconductivity of a compoundif the compound has any ions/electrons that are free tomove around and carry the electricitysolubility of a compoundif the compound has a similar solubility to the compounddissolving it – like dissolves like and if the energy/stabilitygained from dissolving is greater than the energy/stabilitylost from breaking the bonds to dissolve
Ionic Compounds
Structure and bonding in ionic compoundsBondingIonic compounds consist of ions held together byionic bonds. Ionic bonds are strong bonds.StructureThese bonds hold ionic compounds together in aregular 3‐dimensional lattice. Each ion issurrounded by ions of the opposite charge.ionicionsionic bonds
Properties of ionic compoundsMelting point Ionic compounds have high melting points because a lot of energyis required to break the electrostatic attractions between the ions.Conductivity Ionic compounds can only conduct electricity when they aredissolved in water or are molten as there are ions free to move.Ionic compounds can not conduct electricity as a solid, as the ionsare not free to move.Solubility Some ionic compounds are soluble in water (remember back toCHEM2.2) as the water can pull the ions apart from each other.
Properties of ionic compoundsBrittleness Ionic compounds are brittle because of their 3‐dimensionallattice structure. If they are knocked out of line the anions repelthe anions and the cations repel the cations and the compoundbreaks apart. ‐‐ ‐‐ ‐ ‐ ‐ ‐ ‐ ‐ ‐ ‐ ‐‐ ‐ ‐ ‐ ‐ ‐ ‐ Malleability and ductility Ionic compounds are not malleable or ductile as the ionicbonds are directional
Do now:Why are some ionic compounds soluble in water?Why do ionic compounds have high melting points?Why can ionic compounds not conduct electricity when theyare solid?
Metallic Compounds
Structure and bonding in metallic compoundsBondingMetallic compounds consist of positive nucleisurrounded by electrons. The nuclei and electrons are held togetherby metallic bonds. Metallic bonds are strong bonds.StructureMetallic bonds are non‐directional, and the sea of electronssurround the positive nuclei.In the exam you will be asked to fill in a table like this:metallicatomsmetallic bonds
Sea of electronsThe electrons are thevalence electrons of themetal (the electrons fromthe outer shell of theatom).Metallic bonds are strongbut non‐directional (thenuclei can move around).
Properties of metallic compoundsUse your knowledge of metallic bonding to see if you canpredict the following properties of metallic compounds andexplain why they might have these properties.Melting pointHighLowConduct electricityYesNoDissolve in waterYesNo
Properties of metallic compoundsMelting point Metallic compounds have high melting points because a lot ofenergy is required to break the electrostatic attractions betweenthe cations and electrons.Conductivity Metallic compounds can conduct electricity as there are electronsfree to move.Solubility Metallic compounds are not soluble in water, as the water can notpull the cations away from the electrons.
Properties of metallic compoundsMalleability and ductility Metallic compounds are ductile (stretchy) and malleable (bendy)because the metallic bonds are non‐directional (sea of electronsallow the nuclei to move).Brittleness Metallic compounds are not brittle because the metallic bonds arenon‐directional (sea of electrons allow the nuclei to move).
ComparisonsUse your knowledge of the structure and bonding in metals andionic compounds to compare and contrast the following uses ofmetals and ionic compounds Metals like tungsten are used in light bulbs because they canconduct electricity as solids, but ionic compounds can not.Metals like copper are used in wires because they can bestretched into wires, but ionic compounds shatter when force isapplied.Zinc does not dissolve in water but zinc chloride can dissolve inwater.
Do now:In your own words explain the similarities and differencesbetween metallic and ionic structure.
Types of bondsIONICCOVALENTMETALLICeg coppereg sodiumchloride (salt)SIMPLE MOLECULAReg carbon dioxide,waterGIANTMOLECULAReg diamond,graphite
Covalent NetworkCompounds
Structure and bonding in covalent networkcompoundsBondingThe atoms in covalent network compounds are held togetherby covalent bonds. Covalent bonds are strong.StructureDiamond and silica – atoms are covalently bonded in regular 3‐dimensional networks, each atom is bonded to 4 other atoms.Graphite – atoms are covalently bonded in 2‐dimensionalsheets with free electrons between the sheets, each atom isbonded to 3 other atoms.covalentnetworkatomscovalentbonds
Do now:What type of substance am I?(a) I have a melting point of 3500 C and can not conductelectricity. I am an colourless crystal. Am I an ionic compoundor metallic compound or covalent network compound?(b) I have a melting point of 801 C and I shatter easily. I don’tconduct charge when I am a solid but I can when I am molten.Am I an ionic compound or metallic compound or covalentnetwork compound?What aspects of structure and bonding give these substances theirproperties?
Diamond and silicaIn diamond each atom is a carbon atom.In silica there is a 1:2 ratio of Si:O (SiO2).GraphiteEach atom is a carbon atom.
Properties of covalent network compoundsUse your knowledge of bonding in covalent networkcompounds to see if you can predict the following properties ofmetallic compounds and explain why they might have theseproperties.Melting pointHighLowConduct electricityYesNoDissolve in waterYesNo
Properties of covalent network compoundsMelting point Covalent network compounds have high melting points because alot of energy is required to break the covalent bonds.Conductivity Diamond and silica can not conduct electricity, because there areno free electrons.Graphite can conduct electricity, because there are free electronsbetween the layers of graphite.Solubility Covalent network compounds are not soluble in water, as thewater can not pull the atoms away from each other.
Properties of covalent network compoundsBrittleness Covalent network compounds not brittle because of theirstrong covalent bondsMalleability and ductility Covalent network compounds are not malleable or ductile asthe covalent bonds do not allow the atoms to move.
covalentbondsCovalent MolecularcovalentbondsCompoundscovalentbonds
Do now:Below are some pictures of covalent network compounds andcovalent molecular compounds. What differences and similaritiesdo you notice between these two different types of compounds?
Structure and bonding in covalent molecularcompoundsBondingThe atoms in covalent molecular compounds are held togetherby covalent bonds. Covalent bonds are strong.StructureThe individual molecules are held together weak bondsbetween moleculesby weak intermolecular forcescovalent bondbetween atomscovalentmolecularatomsintermolecularforces
covalent bondbetween atomsBonds betweenatoms are calledintra‐molecularbondsweak bondsbetween moleculesBonds betweenmolecules arecalled inter‐molecular bondsThink of it as like the difference between intranet and internet.Intranet – within a companyInternet – between the world
Properties of covalent molecular compoundsUse your knowledge of bonding in covalent molecularcompounds to see if you can predict the following properties ofmetallic compounds and explain why they might have theseproperties.Melting pointHighLowConduct electricityYesNoDissolve in waterYesNo
Properties of covalent network compoundsMelting point Covalent molecular compounds have low melting points because asmall amount of energy is required to break the intermolecularforcesThe mass of a compound affects the melting point – the heavier thecompound the more energy required to break the bonds betweenthe moleculesConductivity Covalent molecular compounds can not conduct electricity,because there are no free electrons.Solubility The solubility of covalent molecular compounds depends on theirintermolecular forces.
Arrange the cards in your envelope under these fourheadingsMetallicIonicCovalentNetworkYou should have under each heading: examples of each compound properties of each compound the type of particles each compound has.MolecularCovalent
Putting it all togetherType tAtomsHighNoNoIonsMelting Conductivity SolubilitypointOnly whenHighIn waterliquidMolecular Molecules LowNoDepending ofpolarity ofcompoundand solvent
What type of solid am I?Choose from ionic, metallic, covalent network or molecular I am a white crystalline solid with a meltingpoint of 80 C, I can not conduct electricity I am a white crystalline solid with a meltingpoint of 801 C, I am soluble in water andconduct electricity when dissolved in water I am an off‐white crystalline solid with amelting point of 1600 C, I can not conductelectricityDiscuss in groups how the properties of eachsubstance allowed you to determine the type ofsolid. Discuss what the properties tell you aboutthe structure and bonding in the solid.
2013 Exam Q2 a)
2013 Exam Q2 b) (i)What key words are used in the question? Write down fiveWhat key words will we use in our answer? Write down threeWhat key statements will we make in our answer? Write downthree
Achieved level answermention melting point?links to structure and property need to be clearer
Excellence level answer
Excellence level answer
2013 Exam Q2 b) (ii)What key words are used in the question? Write down fiveWhat two properties of copper and graphite is the questionasking you to compare?What key words will we use in our answer? Write down threeWhat key statements will we make in our answer? Write downthree
2013 Exam Q2 b) (ii)Is this answer A, M or E? What is good about it?What could be improved?
Do now:Answer the following question. It is Q 2 b from the 2012 exam.Silicon dioxide has a melting point of 1770 C.Explain why silicon dioxide has a high melting point by referringto the particles and the forces between the particles in thesolid.Make sure you state the type of compound, the type of bondingand the structure of the compound, and use the type of bondingand the structure to explain the property.
Merit level answerWhat is missing from this answer?The type of compoundThe type of particles
Excellence level answer
Assessment scheduleACHIEVEMENTMERITEXCELLENCEGive your answer a grade1 point of achieved for AExplains answer for M (basically both A points)Explains and justifies answer for E (because AND therefore/this means that)
This is the answer, what is thequestion?Both graphite and copper chloride are able to conduct electricity.Compounds can conduct electricity when there is free electrons orions that are able to move to conduct the charge.Graphite is a covalent network solid. It has strong covalent bondsbetween atoms and is arranged in layer of 2‐dimensional sheetscovalently bonded t each other. Between these sheets are electronsthat are free to move. This allows graphite to conduct electricity as asolid.Copper chloride is an ionic solid so it can only conduct electricitywhen it is molten or dissolved in water. As a solid the ions are heldtogether in a 3‐dimensional lattice that does not allow the ions tomove, but when copper chloride is dissolved in water or melted theions are free to move around and this allows copper chloride toconduct electricity.
This is the answer, what is thequestion?Two of the following substances can conduct electricity.Copper chlorideDiamondGraphiteIodineSilicon dioxideWrite the names of the two substances and discuss, with reference totheir structure and bonding, why the substances you chose are able toconduct electricity. Include any conditions that are required.
Bonding Ionic compounds consist of ions held together by ionic bonds. Ionic bonds are strong bonds. Structure These bonds hold ionic compounds together in a regular 3‐dimensional lattice. Each ion is surrounded by ions of the opposite charge. Structure and bonding in ionic compo
from electric shock. Bonding and earthing are often confused as the same thing. Sometimes the term Zearth bonding is used and this complicates things further as the earthing and bonding are two separate connections. Bonding is a connection of metallic parts with a Zprotective bonding conductor. Heres an example shown below.
comparing with Au wire bonding. Bonding force for 1st bond is the same range, but approx. 30% higher at 2nd bonding for both Bare Cu and Cu/Pd wire bonding but slightly lower force for Bare Cu wire. Bonding capillary is PECO granular type and it has changed every time when new cell is used for bonding
Modern Chemistry 1 Chemical Bonding CHAPTER 6 Chemical Bonding SECTION 1 Introduction to Chemical Bonding OBJECTIVES 1. Define Chemical bond. 2. Explain why most atoms form chemical bonds. 3. Describe ionic and covalent bonding. 4. Explain why most chemical bonding is neither purely ionic or purley 5. Classify bonding type according to .
Application of bonding system The bonding systems have a valuable application in dentistry such as: sealant, enamel and dentin bonding system, amalgam-bonding system, resin-composite cement, crown and bridge cement and orthodontic bonding system.5 Principles of adhesion Bonding of resins to tooth structure is a result of four potential .
Metallic Bonding Metallic Bonding The metallic bond consists of positively charged metallic cations that donate electrons to the sea. The sea of electrons are shared by all atoms and can move throughout the structure. Metallic Bonding Metallic Bonding In a metallic bond: – The resulting bond is a cross between covalent and ionic .
Pure covalent bonding only occurs when two nonmetal atoms of the same kind bind to each other. When two different nonmetal atoms are bonded or a nonmetal and a metal are bonded, then the bond is a mixture of cova-lent and ionic bonding called polar covalent bonding. Covalent Bonding In METALLIC BONDING the valence electrons are
the gold bonding wire and gold board metallization. Power and time relate to the ultrasonic generator settings used to “ultrasonically soften,” the bonding wire. Tool force is the amount of weight applied to the bonding wire to mechanically couple the bonding wire to the bonding pad surface. D
the Cu wire bonding technology presents a promising alternative. 2.2. Cu wire bonding In general, to judge the wire bonding ability, we control the bonding ball shear and the bonding wire pull (Fig. 2.3). Value set-tings differ according to the type of assembly package. Moreover, wire diameters also differ depending on whether Au or Cu was used.
