Ionic Bonding

Writing Formulae

Naming Compounds

Atoms and Ions Chemical Bond —force that holds 2

atoms together Atoms are neutral=same number of

protons as electrons Ion—atom that has lost or gained

electrons (it has a charge of + or -)

Remember Only electrons can

move Atoms gain or lose

electrons to achieve a noble gas configuration

To be stable

Keeping Track of Electrons The electrons responsible for the

chemical properties of atoms are those in the outer energy level.

Valence electrons - The s and p electrons in the outer energy level.

Core electrons -those in the energy levels below.

Keeping Track of Electrons Atoms in the same column have the

same outer electron configuration. Have the same valence electrons. Easily found by looking up the group

number on the periodic table. Group 2A - Be, Mg, Ca, etc.- 2 valence electrons

Electron Dot diagrams A way of keeping track of

valence electrons. How to write them Write the symbol. Put one dot for each

valence electron Don’t pair up until they

have to

X

The Electron Dot diagram for Nitrogen

Nitrogen has 5 valence electrons.

First we write the symbol.

NThen add 1 electron at a time to each side.Until they are forced to pair up.

Write the electron dot diagram for

Na Mg C O F Ne He

Electron Configurations for Cations

Metals lose electrons to attain noble gas configuration.

They make positive ions. If we look at electron configuration it

makes sense. Na 1s22s22p63s1 - 1 valence electron Na+ 1s22s22p6 -noble gas configuration

Electron Dots For Cations Metals will have few valence electrons

Ca

Electron Dots For Cations Metals will have few valence electrons These will come off

Ca

Electron Dots For Cations Metals will have few valence electrons These will come off Forming positive ions

Ca+2

Electron Configurations for Anions *

Nonmetals gain electrons to attain noble gas configuration.

They make negative ions. If we look at electron configuration it

makes sense. S 1s22s22p63s23p4 - 6 valence electrons S-2 1s22s22p63s23p6 -noble gas

configuration.

Electron Dots For Anions Nonmetals will have many valence

electrons. They will gain electrons to fill outer shell.

P P-3

Stable Electron Configurations All atoms react to achieve noble gas

configuration. Noble gases have 2 s and 6 p electrons. 8 valence electrons . Also called the octet rule.

Ar

Compounds 2 atoms bonded

together Follow the Law of

Definite Proportion—have a constant composition—the same # of atoms every time

3 Types of compounds

Ionic Bonds Covalent or Molecular Bonds

Metallic Bonds

Ionic Bonds Made by transferring electrons Made of cations (metals) and anions

(nonmetals) The e- lost by the cation is gained by

the anion The cations and anions surround each

other Smallest piece is a Formula Unit

Ionic Bonding

Ionic Bonding Anions and cations are held together by

opposite charges. Packed into a regular repeating pattern

that balances the forces of attraction and repulsion between the ions forming a crystal

Very strong bond Ionic compounds are called salts.

Properties of Ionic Compounds Crystalline structure. A regular repeating arrangement of ions

in the solid. Ions are strongly bonded. Structure is rigid. High melting points- because of strong

forces between ions.

Crystalline structure

Do they Conduct? Conducting electricity is allowing charges

to move. In a solid, the ions are locked in place. Ionic solids are insulators. When melted, the ions can move around. Melted ionic compounds conduct. First get them to 800ºC. Dissolved in water they conduct.

Ionic solids are brittle

+ - + -+- +-

+ - + -+- +-

Ionic solids are brittle

+ - + -

+- +-+ - + -

+- +-

Strong Repulsion breaks crystal apart.

Writing the formula for compounds and Naming

compoundsLearning to speak the language

Chemical Formula Shows the kind

and number of atoms in the smallest piece of the substance

Nicotine C10H14N2

For Ionic Compounds: Systematic Naming

There are too many compounds to remember the names of them all

Compound-2 or more elements chemically combined

Pure substance Name tell how many and what kind of

atoms

Remember –Ionic Bonds Anions and cations held together by

opposite charges Called salts Simplest ratio is called formula unit Bond is formed by transfer of electrons Electrons are transferred to achieve a

noble gas configuration

Ionic bonding or Formula Unit Shows lowest

whole # ratio of atoms in the crystal lattice

NaCl MgCl2

Charges on Ions You can tell charge of an atom by its

location Elements in the same group have

similar properties including the charge when they are ions

Oxidation number -the charge of the ion

+2

+1

+3 -3 -2 -1

Naming ions We will use the systematic way. Cation- if the charge is always the same

(Group A) just write the name of the metal.

Transition metals can have more than one type of charge.

Indicate the charge with roman numerals in parenthesis.

Name these Na+1 Ca+2 Al+3 Fe+3 Fe+2 Pb+2 Li+1

Write Formulas for these Potassium ion Magnesium ion Copper (II) ion Chromium (VI) ion Barium ion Mercury (II) ion

Naming Anions Anions are always the same. Change the element ending to – ide F-1 Fluorine

Naming Anions Anions are always the same. Change the element ending to – ide F-1 Fluorine Fluor + ide =

Fluoride

Name these Cl-1

N-3 Br-1 O-2

Ga+3

Write these Sulfide ion iodide ion phosphide ion Strontium ion

Polyatomic ions Group of atoms covalently bonded together

that gain or lose an electron LEARN YOU POLYATOMIC IONS! Oxyanion –polyatomic ions composed of an

element bonded to one or more oxygen atoms

– Ate ions

– Ite ions

– Per

– hypo

Polyatomic ions Sulfate SO4

-2

Sulfite SO3-2

Carbonate CO3-2

Chromate CrO4-2

Dichromate Cr2O7-

2

Phosphate PO4-3

Phosphite PO3-3

Ammonium NH4+1

Monatomic vs Polyatomic anions

S-2 monatomic Sulfide ion N-3 monatomic Nitride ion Bromide Selenide

SO4-2 polyatomic

Sulfate ion NO3

- polyatomic Nitrate PO4

-3 Phosphate ion

Naming Binary Ionic Compounds Binary Compounds - 2 elements. Ionic - a cation and an anion. To write the names just name the two

ions. Easy with Representative elements. Group A NaCl = Na+ Cl- = sodium chloride

MgBr2 = Mg+2 Br- = magnesium bromide

Naming Binary Ionic Compounds The problem comes with the transition

metals. Need to figure out their charges. The compound must be neutral. same number of + and – charges. Use the anion to determine the charge

on the positive ion.

Naming Binary Ionic Compounds

Write the name of CuO Need the charge of Cu O is -2 copper must be +2 Copper (II) chloride Name CoCl3

Cl is -1 and there are three of them = -3 Co must be +3 Cobalt (III) chloride

Naming Binary Ionic Compounds Write the name of Cu2S.

Since S is -2, the Cu2 must be +2, so each one is +1.

copper (I) sulfide Fe2O3 Each O is -2 3 x -2 = -6 3 Fe must = +6, so each is +2. iron (III) oxide

Naming Binary Ionic Compounds Write the names of the following KCl Na3N

CrN

Sc3P2

PbO

PbO2

Na2Se

Ternary Ionic Compounds Will have polyatomic ions At least three elements name the ions

NaNO3

CaSO4

CuSO3

(NH4)2O

Ternary Ionic Compounds LiCN Fe(OH)3

(NH4)2CO3

NiPO4

Writing Formulas The charges have to add up to zero. Get charges on pieces. Cations from name on table. Anions from table (ide) or

polyatomic. Balance the charges by using

subscripts.

Ionic Bonding

Na Cl

Ionic Bonding

Na+ Cl-

Ionic Bonding All the electrons must be accounted for!

Ca P

Ionic Bonding

Ca P

Ionic Bonding

Ca+2 P

Ionic Bonding

Ca+2 P

Ca

Ionic Bonding

Ca+2 P-3

Ca

Ionic Bonding

Ca+2 P-3

Ca P

Ionic Bonding

Ca+2 P-3

Ca+2 P

Ionic Bonding

Ca+2 P-3

Ca+2 P

Ca

Ionic Bonding

Ca+2 P-3

Ca+2 P

Ca

Ionic Bonding

Ca+2 P-3

Ca+2P

-3

Ca+2

Ionic Bonding

Ca3P2

Formula Unit

Writing Formulas Write the formula for calcium chloride. Calcium is Ca+2 Chloride is Cl-1 Ca+2 Cl-1 would have a +1 charge. Need another Cl-1

Ca+2 Cl2-1 1 (+2) and 2 (-1)=0

CaCl2

Write the formulas for these Lithium sulfide tin (II) oxide tin (IV) oxide Magnesium fluoride Iron (III) phosphide Iron (III) sulfide

Writing Ternary Ionic Write the formula for calcium chlorate. Calcium is Ca+2 Chlorate is ClO3

-1

Ca+2 ClO3-1

Need another ClO3-1

When you need to have more than one polyatomic ion you must use PARENTHESES

Ca(ClO3) 2

Write the Formula Lithium sulfate tin (II) hydroxide tin (IV) cyanide Magnesium dichromate Iron (III) Phosphate Iron (III) sulfide