Basics of Bonding

Types of Bonding Bonds: how atoms are held together 3 main bonding types Ionic (strong) Covalent (weak) Metallic (strong)

Ionic Between metals and nonmetals Both form ions Ions are attracted to each other By nuclear charge Metals form cations lose electrons Nonmetals form anions gain electrons

Ions formed Main group elements typically have set charges. There are exceptions to this guideline

Transition Metal Mainly D-block metals/ groups 3-12 There are exceptions Change oxidation states / charges from 1 + to 4 + Depending on what they are bonded with To determine charge Find the charge of the NON-METAL Transition metals form cations

Polyatomic Ions Nonmetals, covalently, bonded together that have an overall charge Poly: many Atomic: atoms Ions: charged they form both cations and anions Must memorized grouping and charge Have a different naming system DON’T FORGET THE QUIZLET

Why do compounds form ? STABILITY!!!! All ions either lose or gain electrons Octet Rule: To have a FULL (2 or 8) outer shell Nonmetals gain electrons Metals lose electrons Oppositely charged ions attract to form bonds

Creating Ionic Compounds Find the metal on the periodic table Determine type of atom Metal, nonmetal, transition metal Determine charge of atom How many electrons does it gain/lose Metals lose (cation) Nonmetals gain(anion) Equalize the charge By using subscripts which tell number

Let's form some “normal” ionic compounds! Sodium Fluoride Na1+ F1- (1+)+(1-) = 0 NaF Calcium Oxide Ca2+ O2- (2+)+(2-) = 0 CaO Calcium Fluoride Ca2+ F1- (2+)+(1-) = 1+ (2+)+ ___ (1-) = 0 CaF2 Sodium Oxide Na1+ O2- (1+) + (2-) = 1- ___ (1+) + (2-) = 0 Na2O 2 2

How to determine a Transition Metal Charge From the Name The roman numeral is the charge of the transition metal From the formula Determine the NON- METAL’S or Polyatomic ions’ charge Equalize the compound to neutral Make charges equal and opposite Use subscripts

Lets Determine Charge! FeO Fe: ? O: 2- _____ + 2- = 0 Fe2S3 Fe: ? Manganese (II) Oxide Mn: O: 2- 2 3

Naming Ionic Compounds The cation keeps its full name Anion take the root of the word Change the ending to “ide” Exception: polyatomic ions always keep their full name Put them together

Lets name some compounds! CuCl2 Li(C2H3O2)   V2Se3   Mn3N4 BeO Na2(SO4) copper (II) chloride lithium acetate   vanadium (III) selenide   manganese (IV) nitride beryllium oxide sodium sulfate

Properties of Ionic Bonds Strong Form Crystalline solids Network solids Can conduct electricity when molten Aqueous High melting points Hard Brittle Electronegativity Difference > 1.9

Covalent When atoms share electrons Between non-metals Not all sharing is equal

Why do they form ? Valence shell/ orbitals over lap to share electrons Covalent compounds can share One pair Two pairs  Three pairs  Stability Share electrons so valence shell is full Duet (Hydrogen and Helium only) or Octet Lowest possible energy

Steps to making covalent compounds NO CHARGES ARE INVOVOLED  Amount is indicated by number prefix in the name

Naming Covalent Compounds First element keeps it full name If there is more then one of the element Gets a number prefix Second element keeps the root of the name Ends in “ide” Always gets a number prefix

Lets make some Covalent Compounds carbon tetrafluoride silicon dioxide dinitrogen trisulfide phosphorus mononitride hydrogen gas carbon disulfide CF4 SiO2 N2S3 PN H2 CS2

Lets Name Covalent Compounds Carbon Monoxide Carbon Dioxide Dinitrogen Trioxide Nitrogen gas Nitrogen MonoPhosphide 6. Sulfur Dichloride CO CO2 N2O3 N2 NP SCl2

Properties of Covalent Bonds Weak Liquids Gases Nonconductive Low melting points Flows easily Electronegativity difference of 0.3 < EN < 1.9

Metallic Bonding Force that keeps metal atoms together Delocalization of electrons Sea of electrons flowing between metal cations Leads to metallic properties Ductility Pulled into wires Malleability Hammered into sheets Conductivity Can move electricity

Properties of Metallic Bonds Strong Solids Extremely conductive High melting points Hard Malleable Ductile Electronegativity Difference < 0.3