U7D2Writing and Naming Ionic Formulas

U7D2: Writing and Naming Ionic FormulaHW: WS: Formula Writing and Naming Practice

Do Now: 1.HW out for check

2. Is [Cd]-2 the correct ion dot diagram for a

Cadmium ion? Explain.

Today: • Review• Naming Ionic Compounds• Practice!!!• TTL

The three steps in forming an ionic bond are:

1. ____________________________________________

2. ____________________________________________

3. ____________________________________________

Metal loses e- to nonmetal becoming a cation.

Nonmetal gains e- from metal to become an anion.

Cation and anion attract to form an ionic compound.

Period 1

Let’s practice

More????

• So.. Fist to Five

Fist (not understanding need help)

Five (feel I can teach it)

• Show me where you stand

Ionic Formula Writing• The number of each type of ion that will form the new compound will depend on the size or magnitude of the charges (oxidation states).

• The charges must add up to zero.

• Ex. sodium reacts with chlorine, • sodium forms a Na+1 ion & chlorine forms a Cl-1 ion. • Only one of each ion is necessary ->• the charges add up to zero: (+1) + (-1) =0

the formula of the new compound, sodium chloride, is simply NaCl.

but what if the charges aren’t equal and opposite?

• If sodium reacts with oxygen, • sodium still forms a Na+1 ion but oxygen forms a O-2 ion.

• The new compound, sodium oxide, will require 2 Na+1 for every O-2: 2(+1) + (-2) =0 .

• The formula for sodium oxide is Na2O.

Remember:• the charges are written as superscripts (Na+1) and the counters in formulas are written as subscripts (Na2O).

• Positive ions are written first and negative ions are written second in a formula.

• Lazy chemists do not bother to write 1 as counter in a formula. The element's symbol stands for the 1.

• Ionic formulas are always written in lowest terms. => an empirical formula.

• NaCl and Na2O are binary (2 element) ionic cds.

VI. DETERMINING CHARGES: • The oxidation state or number is the charge or apparent charge an atom has in a compound.

• To determine the charge, simply look at the Periodic Table for the oxidation states of the element.

• For nonmetals it is the FIRST (top) oxidation state ONLY.

• For many metals, there is only one possibility for the charge.

• Transition metals and those metals close to the “crack”, there are more than one charge.

Look up the charges on the following: • Remember to write the charges as superscript

+2 +1 -1 -3 +1

-2 +2 +3 +1 +2 +3 -1

Draw a Lewis Dot structure for (p. 3 margin) FeO and Fe2O3

WRITING BINARY FORMULAS • The ions of the elements combine in such a way that the charges have to add up to zero.

• Metal or positive ion (cation) is written FIRST

• Nonmetal or negative ion(anion)is written SECOND.

• The number one,1, is not written in the formula

ex. NaCl.

• Only the number in the charge for each ion is criss-crossed down and turned into subscripts.

• Always check that the formula is in LOWEST terms.

• K+1 O-2 K O K2O1 or K2O

• Pb+4 O-2 -> Pb O -> Pb2O4 simplifies to ______ PbO2

So… Let’s look at the different combinations we can have…

XY

XY

XY

XY2

XY3

X2Y

X3Y

X3Y2

X2Y3

XY2

VII. NAMING • The name of the positive ion is followed by the name of the negative ion.

• Group 1 & 2 Metals, Metals with ONE charge LISTED: name of the metal ONLY

• For nonmetals, the ending of the nonmetal’s name with the ending changed to IDE.

Let’s try!• Name ionic compounds:

• NaF: • AlN:

• AgBr:

• Na3P:

• Li2O:

• PbCl2 :

sodium fluoride

Aluminum nitride

Silver bromide

sodium phosphide

Lithium oxide

Lead (II) chloride

Practice

LiF

AlCl3SrS

K3N

Mg3P2

Lithium fluoride

Aluminum chlorideStrontium sulfide

Potassium nitride

Magnesium phosphide

How about backwards? Name -> formula• Determine the elements involved, their charges & then write the formulas. Look up charges on the PT for the ions.

Na+1

Ca+2

Zn+2

Be+2

K+1

Br-1

O-2

Cl-1

F-1

I-1

NaBr

CaO

ZnCl2

BeF2

KI

VIII. DETERMINING CHARGES AND NAMING of TRANSITION ELEMENTS

• Transition elements (metals) and some other metals located near the “crack”, can have more than one charge.

• Either you will be told which one to use or the charge can be determined from the formula.

• To distinguish between the different oxidation states or charges, a roman numeral equal to the charge on the ion is used to name the ion.

• Ex, tin comes in two charges, +2 and +4. • Sn+2 is called tin (II) and Sn+4 is called tin (IV). • The formula of tin (II) oxide is SnO and • the formula of tin (IV) oxide is SnO2.

• The charge on the tin makes a difference!

• If Fe2O3 is iron (III) oxide, what would be the formula for iron (II) oxide? _____

• (Draw the Ion dot diagram for

Iron (II) oxide)

FeO

ROMAN NUMERALS: +1 ___, +2 ____, +3 ____, +4 ____, +5 ____, +6 _____I II III IV V VI

Cu2O

Ni2O3

FeI2

Au3N

PbO2

Copper (I) oxide

Nickel (III) sulfide

Iron (II) iodide

Gold (I) nitride

Lead (IV) oxide

Going Backwards!

Cu+1 CuF

Cu+2

Au+3

Sn+4

Pb+2

F-1

Cl-1

O-2

O-2

P-3

CuCl2

Au2O3

SnO2

Pb3P2

Naming the Ionic Compounds from JUST the Formula• Determine if it has a metal with more than 1 charge or not • If yes, then look up the nonmetal’s charge and write the formula with each of

the charges. • Ex . FeO Fe+2 O-2 FeO• Fe+3 O-2 Fe2O3

• a) Since the formula with Fe+2 matches, FeO, then Fe+2 was used.• Use the Roman numeral equal to this charge in the middle of the • compound’s name. Iron (II) • b) Change the name of the non-metal to the ending “ide”. Oxide• Iron (II) Oxide• If no, then just use the metal’s name and change the name of the non-metal to the

ending “ide”.• Ex. AgCl Ag+1 +1 is the only charge • Silver Chloride

• Remember any element in Groups 1 & 2 have ONLY one Charge!! No Roman Numeral ever!!!

Silver chloride

Lead (IV) oxide

Tin (II) oxide

Sodium phosphide

Zinc bromide

Iron (III) oxide

Gold(III) iodide

Chromium(III) Nitride

Copper(II) oxide

Calcium nitride

IX. POLYATOMIC IONS (PAI)• A. Reference Table E• Groups of atoms bond

together by sharing electrons to form ions.

• one of the atoms in the group brings along a charge and group of atoms is not neutral

• “many atom” ion.

Complete this chart using reference table E.

carbonate

acetate

sulfate

chlorate

hydroxide

NO3 -

ClO2 -

CrO4 -2

SO3 -2

PO4 -3

• What type of charge do most of the PAI have? __________________

• Most of these PAI end in _________ or __________

• Two important exceptions are the positive ion

_________ (ammonium) and the negative ion

_________ (hydroxide).

negative

-ate -ite

NH4 +

OH-

B. Writing and Naming Compounds with Polyatomic Ions

Rules:• The formula must be in lowest terms• the charges must add up to zero. • Parenthesis are used around the polyatomic ion when more

than one of these ions is necessary in a formula: (NH4)2O.

• To name compounds with polyatomic ions, use the name of the polyatomic ion listed on the reference table.

• Ex: (NH4)2O is ammonium oxide;

• K2CO3 is potassium carbonate.

• ternary ionic compounds: K2CO3 and NaClO4

• binary ionic compounds: K2O and NaCl

Try your hand at these!

KNO3

Al(ClO3)3

SrSO4

KNO2

Mg3(PO4)2

Potassium nitrate

Aluminum chlorate

Strontium sulfate

Potassium nitrite

Magnesium phosphate

Going Backwards! ternary compounds

Na +1

Ca +1

K +1

Au +3

NH3 +

OH -

SO2 -2

CrO4 -2

CO3 -2

ClO4 -

NaOH

CaSO4

K2CrO4

Au2(CO3)3

NH3ClO4

Ok…so how’d we do today

1.

• Cation:__Ag+1__ Anion:___ (OH)-1____• Formula:___________________• Name:_____________________

• 2. • Cation:____ Fe+3__ Anion:___ (PO4)-3___

• Formula:___________________• Name:_____________________