Unit 3: Chemical Bonding and Nomenclature Part 1

States of Matter Solid Liquid Gas Definite shape and volume Cannot be compressed Liquid Definite volume but takes shape of container Gas No fixed volume or shape Uniformly fills container

States of Matter

Phase Change Physical state that involves moving from one state to another Occurs when energy is added or removed

Phase Change

Phase Change Melting: phase change from solid to liquid Freezing: phase change from liquid to solid Temperature where liquid and solid phases coexist at equilibrium is: Melting point of the solid Freezing point of the liquid

Phase Change Vapour: gas Vapour pressure: pressure exert by a gas on its container when it is at equilibrium with its condensed phases (solid or liquid)

Phase Change Boiling: the process of molecules in the liquid phase breaking apart from neighbouring molecules to enter the gas phase Boiling point: temperature when a liquid’s vapour pressure equals the external pressure acting on the liquid surface

Phase Change Evaporation: liquid  gas Condensation: gas  liquid Sublimation: solid  gas Deposition: gas  solid Melting: solid  liquid Freezing: liquid  solid Boiling: liquid  gas

Phase Change and Kinetic Molecular Theory Temperature is a measure of the average kinetic energy of the molecules of a substance Adding energy heats up substances Energy causes more movement of molecules Altering molecular movement alters the state of substances

Phase Change

Phase Change Remember, molecules do not lose their structure when they undergo a phase change H2O is still H2O Steam, water, ice Molecules simply have more space between them

Octet Rule Atoms bond together to obtain a stable electron configuration Atoms gain, lose, or share electrons until they are surrounded by eight valence electrons Some elements require 2 valence electrons (not 8)

Octet Rule Think of your orbital diagrams Elements want to look like the closest noble gas We use Lewis dot diagrams to show valence electrons and help us see how bonding occurs

Lewis Dot Diagrams

Lewis Dot Diagrams Remember, electrons repel each other (negative charge) They don’t want to fill the same orbital if it can be avoided

Common Charges

Remember Electrons are negative Gaining electrons makes charge more negative Losing electrons makes charge more positive Main group elements are lazy and want to look like the closest noble gas Metals want to lose electrons Non-metals want to gain electrons

Ionic Vs. Covalent Bonds In ionic bonding atoms gain and lose electrons Charge (ions) In covalent bonding atoms share electrons No charge (atoms)

Ionic Vs. Covalent Bonds Ionic bonds contain a metal and one or more non-metals Covalent bonds contain only non-metals

Ionic Bonding Atoms form ions by gaining and losing electrons Ionic bonds form a crystal lattice

Ionic Compounds Contain a metal and one or more non-metals Contain ions (charged atoms) due to transfer of electrons NO sharing electrons

Ionic Compounds Electrons are transferred from the metal ion to the non-metal ion Smallest unit is the formula unit 1Na and 1Cl bonded together is one formula unit of NaCl

Ionic Compounds Very high melting and boiling points Crystalline and can be cleaved Broken along smooth flat surfaces Brittle Conduct electricity when dissolved Break into ions

Ionic Compounds Lewis Structures We begin by drawing the individual atoms involved in the bonds NaCl

Ionic Compounds Lewis Structures Then we show the transfer of electrons

Ionic Compounds Lewis Structures Our final structure has square brackets and the charge of the ions

Ionic Compounds Lewis Structures

Binary Ionic Compounds (Type 1 metals) Formula to Name Type 1 metals only have one possible charge Metals keep their name from the table Non-metal is named ending in -ide

Binary Ionic Compounds (Type 1 metals) Formula to Name MgCl2 Magnesium chloride NaCl Sodium chloride AgBr Silver bromide

Binary Ionic Compounds (Type 1 metals) Name to Formula Put the symbols for each element Balance charges (criss cross)

Binary Ionic Compounds (Type 1 metals) Name to Formula Cesium bromide CsBr Cadmium fluoride CdF2 Aluminum sulfide Al2S3 Zinc sulfide ZnS

Roman Numerals I=1 II=2 III=3 IV=4 V=5 VI=6 VII=7 VIII=8 IX=9 X=10

Binary Ionic Compounds (Type 2 metals) Formula to Name Type 2 metals can have more than one charge We must tell other people which form we are talking about Use roman numerals to differentiate metals Name as you did type 1 compounds Add roman numeral in brackets after name of the metal

Binary Ionic Compounds (Type 2 metals) Formula to Name AuCl3 Gold (III) chloride NbN Niobium (I) nitride VBr5 Vanadium (V) bromide

Binary Ionic Compounds (Type 2 metals) Name to Formula Important to remember the roman numeral tells you CHARGE not how many atoms Write symbols for the metal and non-metal Put roman numeral as charge Balance charges (criss cross)

Binary Ionic Compounds (Type 2 metals) Name to Formula Iron (II) bromide FeBr2 Nickel (III) nitride CuN Lead (IV) oxide PbO2

Polyatomic Ions In your booklet Charged chemical species composed of two or more atoms Act as a unit

Polyatomic Ions Name to Formula Follow the rules for the type of compound you are using If there are multiples of the polytomic ion, use brackets Remember they act as a unit

Polyatomic Ions Name to Formula Copper (II) carbonate CuCO3 Magnesium permanganate Mg(MnO4)2 Silver phosphate Ag3PO4

Polyatomic Ions Formula to Name Name by following the rules for the type of compound you are using Don’t change the name of the polyatomic ion

Polyatomic Ions Name to Formula AgCN Silver cyanide Cu3(PO3)2 Copper (II) phosphite Mn(HCO3)2 Manganese (II) hydrogen carbonate Manganese (II) bicarbonate

Hydrates Formed by the addition of water or its components to another substance Substances without water are called anhydrous Water molecules form lattice around central compound

Prefixes Mono=1 Di=2 Tri=3 Tetra=4 Penta=5 Hexa=6 Hepta=7 Octa=8 Nona=9 Deca=10 Tell you the number of water molecules that are present Example: Hexahydrate = 6 water molecules

Hydrates Formula to Name Name the base compound by following rules Add “hydrate” with the appropriate prefix

Hydrates Formula to Name LiClO4 • 3H2O Lithium perchlorate trihydrate NiSO4 • 6H2O Nickel (II) sulfate hexahydrate

Hydrates Name to Formula Write the formula for the base compound by following previous rules Separate water molecules from central compound with “•” Write H2O with appropriate coefficient

Hydrates Name to Formula Copper (II) sulfate pentahydrate CuSO4 • 5H2O Magnesium carbonate pentahydrate MgCO3 • 5H2O

Covalent Bonds Bonds made between non-metal atoms Electron sharing due to similar affinities for electrons No transfer of electrons Smallest unit is the molecule 1C and 4H bonded together is one molecule

Covalent Compounds Low melting and boiling points Pliable in solid form Do not conduct electricity when dissolved Do not ionize in solution

Covalent Compounds and Lewis Structures We begin by drawing the individual atoms involved in bonding Atom needing the most electrons goes in the middle

Covalent Compounds and Lewis Structures We circle the electrons that will be shared by the atoms

Covalent Compounds and Lewis Structures Where there are 2 electrons circled by 2 atoms we replace the electrons with a line Represents a bond

Covalent Compounds and Lewis Structures

Covalent Compounds and Lewis Structures When 2 electrons are shared it is a single bond (1 shared pair) Can have multiple bonds 4 electrons shared (2 shared pairs) = double bond 6 electrons shared (3 shared pairs)= triple bond

Covalent Compounds and Lewis Structures For more complicated compounds: Add up total valence electrons of bonding atoms This is the number of electrons we need in our final structure Draw one bond between the central atom and the other bonding atoms Each bond counts as using up 2 of the electrons we started with Draw in the valence electrons on the atoms Borrow electrons to give the central atom a full octet

Covalent Compounds and Lewis Structures Draw the Lewis Structure of the following: CO2 HCN COS

Covalent Compounds Formula to Name Prefixes Mono=1 Di=2 Tri=3 Tetra=4 Penta=5 Hexa=6 Hepta=7 Octa=8 Nona=9 Deca=10

Covalent Compounds Formula to Name Write the names of the elements present Change ending to –ide for last element Add prefixes to match the number of atoms of each element

Covalent Compounds Formula to Name CH4 Carbon tetrahydride CO Carbon monoxide N2S3 Dinitrogen trisulfide

Covalent Compounds Name to Formula Write the symbols for each element in the compound Use the prefixes as the subscripts in the formula

Covalent Compounds Name to Formula NCl3 Nitrogen trichloride CS2 Carbon disulfide BrCl Bromine monochloride