Symbols X A Z Na 23 11. Chemical Bonds n The forces that hold atoms together. n Covalent bonding - sharing electrons. n Makes molecules. n Chemical formula-

SymbolsSymbols

XA

Z

Na23

11

Chemical BondsChemical Bonds The forces that hold atoms together.The forces that hold atoms together. Covalent bonding - sharing electrons.Covalent bonding - sharing electrons. Makes molecules.Makes molecules. Chemical formula- the number and type of Chemical formula- the number and type of

atoms in a molecule. atoms in a molecule. CC22HH66 - 2 carbon atoms, 6 hydrogen atoms, - 2 carbon atoms, 6 hydrogen atoms,

Structural formula shows the connections, Structural formula shows the connections, but not necessarily the shape.but not necessarily the shape.

H

H

H H

H

HC C

There are also other model that attempt to There are also other model that attempt to show three dimensional shape.show three dimensional shape.

Ball and stick.Ball and stick.

IonsIons Atoms or groups of atoms with a charge.Atoms or groups of atoms with a charge. Cations- positive ions - get by losing Cations- positive ions - get by losing

electrons(s).electrons(s). Anions- negative ions - get by gaining Anions- negative ions - get by gaining

electron(s).electron(s). Ionic bonding- held together by the Ionic bonding- held together by the

opposite charges.opposite charges. Ionic solids are called salts.Ionic solids are called salts.

Polyatomic IonsPolyatomic Ions Groups of atoms that have a charge.Groups of atoms that have a charge. Yes, you have to memorize them.Yes, you have to memorize them. List on page 221List on page 221

Periodic TablePeriodic Table

MetalsMetals ConductorsConductors Lose electronsLose electrons Malleable and ductileMalleable and ductile

NonmetalsNonmetals BrittleBrittle Gain electronsGain electrons Covalent bondsCovalent bonds

Semi-metals or MetalloidsSemi-metals or Metalloids

Alkali Metals

Alkaline Earth Metals

Writing FormulasWriting Formulas Two sets of rules, ionic and covalentTwo sets of rules, ionic and covalent To decide which to use, decide what the To decide which to use, decide what the

first word is.first word is. If is a metal or polyatomic use ionic.If is a metal or polyatomic use ionic. If it is a non-metal use covalent.If it is a non-metal use covalent.

Ionic FormulasIonic Formulas Charges must add up to zero.Charges must add up to zero. Get charges from table, name of metal ion, Get charges from table, name of metal ion,

or memorized from the list.or memorized from the list. Use parenthesis to indicate multiple Use parenthesis to indicate multiple

polyatomics.polyatomics.

Ionic FormulasIonic Formulas Sodium nitrideSodium nitride sodium- Na is always +1sodium- Na is always +1 nitride - ide tells you it comes from the nitride - ide tells you it comes from the

tabletable nitride is Nnitride is N-3-3

Ionic FormulasIonic Formulas Sodium nitrideSodium nitride sodium- Na is always +1sodium- Na is always +1 Nitride - ide tells you it comes from the Nitride - ide tells you it comes from the

tabletable nitride is Nnitride is N-3-3 Doesn’t add up to zero.Doesn’t add up to zero.

Na+1 N-3

Ionic FormulasIonic Formulas Sodium nitrideSodium nitride sodium- Na is always +1sodium- Na is always +1 nitride - ide tells you it comes from the tablenitride - ide tells you it comes from the table nitride is Nnitride is N-3-3 Doesn’t add up to zeroDoesn’t add up to zero Need 3 NaNeed 3 Na

Na+1 N-3 Na3N

Ionic CompoundsIonic Compounds Sodium sulfiteSodium sulfite calcium iodidecalcium iodide Lead (II) oxide Lead (II) oxide Lead (IV) oxideLead (IV) oxide Mercury (I) sulfideMercury (I) sulfide Barium chromateBarium chromate Aluminum hydrogen sulfateAluminum hydrogen sulfate Cerium (IV) nitriteCerium (IV) nitrite

Naming compoundsNaming compounds Two typesTwo types IonicIonic - metal and non metal or polyatomics. - metal and non metal or polyatomics. CovalentCovalent- we will just learn the rules for 2 - we will just learn the rules for 2

non-metals.non-metals.

Naming Ionic compoundsNaming Ionic compounds If the cation is monoatomic- Name the If the cation is monoatomic- Name the

metal (cation) just write the name.metal (cation) just write the name. If the cation is polyatomic- name it.If the cation is polyatomic- name it. If the anion is monoatomic- name it but If the anion is monoatomic- name it but

change the ending to change the ending to –ide.–ide. If the anion is poly atomic- just name itIf the anion is poly atomic- just name it Practice.Practice.

Ionic CompoundsIonic Compounds Have to know what ions they formHave to know what ions they form

off table, polyatomic, or figure it outoff table, polyatomic, or figure it out CaSCaS KK22SS

AlPOAlPO44

KK22SOSO44

FeSFeS CoICoI33

Ionic CompoundsIonic Compounds Fe(CFe(C22OO44))

MgOMgO MnOMnO

KMnOKMnO44

NHNH44NONO33

HgHg22ClCl22

CrCr22OO33

Ionic CompoundsIonic Compounds KClOKClO44

NaClONaClO33

YBrOYBrO22

Cr(ClO)Cr(ClO)66