IONIC BONDING

Valence Electrons Electrons in highest occupied

energy level The Roman numeral at the top

of the representative elements gives the number of valence electrons.

LiBr

MgCl2

K3PO

4

SrS

NaOH

KI

CaCl2

IAIIA

IIIA IVA VA VIA VIIA

VIIIA

H

BeLi B C N O F

He

Ne

How many valence electrons do the following elements have? Be - Rb- P- Se- Cl- Ne-

Valence electrons of the following

Be - 2 Rb- 1 P- 5 Se- 6 Cl- 7 Ne- 8

Lewis Dot StructuresLewis Dot Structures Lewis Dot Structures are used to Lewis Dot Structures are used to

show valence electronsshow valence electrons

NeNeP2

P5

S1

S2

P3 P6

Remember P sublevel has 3 orbitals

P4 P1 6 3

5 8

1

2

4

7

Order of filling in electrons

Let’s practice… Write Lewis dot structures for the following

H, He, Li, Be, B, C, N, O, F, Ne,

Na, Mg, Al, S, , Cl

NOTE: The symbol for the element stands for the nucleus & inner electrons

Pause- Check your Pause- Check your answers with your answers with your

teacherteacher

What do you notice happening as you go down any “A” family

group?

On the following, On the following, 1-write the electron 1-write the electron

configurationconfiguration2- underline the valence shell2- underline the valence shell

3-Write the Lewis Dot 3-Write the Lewis Dot structurestructureMagnesium- Mg

Phosphorus- P

Zinc-Zn

Bromine- Br

Tungsten (II)

Uranium (II)

PAUSE TO CHECK ANSWERS PAUSE TO CHECK ANSWERS

WITH the goddess of WITH the goddess of wisdomwisdom

Octet RuleOctet Rule In 1916, Gilbert Lewis came up with the In 1916, Gilbert Lewis came up with the

OCTET RULEOCTET RULE

““Atoms react by changing the number of electrons so as to Atoms react by changing the number of electrons so as to acquire the STABLE configuration of a noble gas.acquire the STABLE configuration of a noble gas.

How many valence electrons do each of the following noble How many valence electrons do each of the following noble gases have?gases have?

He, Ne, Ar, Kr, Xe, RnHe, Ne, Ar, Kr, Xe, RnWrite Lewis Dot Structures for each of the noble gases aboveWrite Lewis Dot Structures for each of the noble gases above

In ionic bonding, metals give electrons and non-metals take In ionic bonding, metals give electrons and non-metals take electrons to become STABLE by mimicking a noble gas.electrons to become STABLE by mimicking a noble gas.

Atoms are electrically neutral. WHY?

If an atom gives away electrons to try to have the same configuration as a noble gas it will have a positive charge.

Ions with a positive charge are called

CATIONS

+

CATIONS

* GIVE AWAY electrons

*Are POSITIVE

* Are made from METALS

Atoms that accept additional electrons are NEGATIVELY CHARGED.

These are negative ions.

Ions with a negative charge

are called ANIONS

ANIONS

* ACCEPT electrons

* Are NEGATIVE

* Made from NON-METALS

The ionization (loss or gain of valence electrons) can be shown using an electron dot structure.

Na * loss of valence e- Na+ + 1 e-

ionization

Mg loss of valence e- Mg 2+ + 2 e-ionization

You try Al

Check on the board your answer and apply this to anions.

*

*

Lewis Dot and Ion Symbols

For the following write the Lewis Dot Structure and then write the ion symbol. The first two will be done for you.

Na* - Na + S - S 2-

Mg F

Ca N

K O

Al Cl

PAUSE to complete ion PAUSE to complete ion handouthandout

Transition metals

The metals can form ions with more than one charge.

Since they are metals they form ________________, or _______ charged ions.

For example, Copper can form a Cu+ or a Cu 2+ ion.

In order to know which ion we are dealing with, we use ROMAN NUMERALS to tell us the charge on the ion.

In our example, Cu+ is called Copper (I); and Cu 2+ is called Copper (II).

Write the ion symbol for the following

Tin (IV); Tin (II); Chromium (II); Chromium (III); Iron (II); Iron (III); Lead (II); Lead (IV)

IONIC COMPOUNDSIONIC COMPOUNDS

A A COMPOUNDCOMPOUND is when 2 or more elements are is when 2 or more elements are chemically bound to each other.chemically bound to each other.

An An IONIC COMPOUNDIONIC COMPOUND is formed between ions. is formed between ions.

An An IONIC COMPOUNDIONIC COMPOUND is formed between a is formed between a positive and negative ion. positive and negative ion.

A A BINARYBINARY(2) ionic compound is formed between a (2) ionic compound is formed between a metal and a non-metal.metal and a non-metal.

The BOND in the ionic compound is formed because opposite charges ATTRACT. Once those positive and negative ions are formed due to the exchange of electrons, the ions are bound together and form a compound.

Turn to the board to get Turn to the board to get examples of ionic compounds.examples of ionic compounds.

Binary Ionic CompoundsBinary Ionic Compounds Are made from a metal and a non-Are made from a metal and a non-

metal.metal. Are made from a positive ion and a Are made from a positive ion and a

negative ionnegative ion ALL IONIC COMPOUNDS are ALL IONIC COMPOUNDS are

electrically NEUTRAL.electrically NEUTRAL. Therefore when forming compounds Therefore when forming compounds

the # of positive charges from the the # of positive charges from the cations must equal the # of negative cations must equal the # of negative charges from the anions.charges from the anions.

Binary Ionic Compounds Cont.Binary Ionic Compounds Cont.

Example Example NaNa++ and Cl and Cl1-1- form a compound NaCl form a compound NaCl

Only one ion of each is required because Only one ion of each is required because the 1+ charge on Na is balanced by the the 1+ charge on Na is balanced by the 1- charge on Cl.1- charge on Cl.

Mg Mg 2+2+ and O and O 2-2- form a compound MgO ; form a compound MgO ; charges are balanced.charges are balanced.

But, what if NaBut, what if Na++ forms a compound with O forms a compound with O 2-2-??

Binary ionic compounds cont.Binary ionic compounds cont.

If NaIf Na++ and O and O2- 2- form a compound, you just form a compound, you just have to make sure the charges are balanced. have to make sure the charges are balanced. An additional sodium ion is needed. An additional sodium ion is needed. NaNa++ with O with O 2-2- form a compound Na form a compound Na22OO NaNa++

This compound requires 2 sodium ions for This compound requires 2 sodium ions for every 1 oxygen ion.every 1 oxygen ion.

Try Ca Try Ca 2+2+ and F and F 1-1- What about Al What about Al 3+3+ and O and O 2-2- ? Try it. ? Try it.

Naming Binary Ionic CompoundsNaming Binary Ionic Compounds Recall the name of cations doesn’t change. A Recall the name of cations doesn’t change. A

sodium ion is simply sodium.sodium ion is simply sodium. Recall the name of anions changes to Recall the name of anions changes to

––ide.ide.

So, you simply name the cation (which always comes So, you simply name the cation (which always comes first) followed by the name of the anion with an –first) followed by the name of the anion with an –ide ending.ide ending.

EX: NaCl – sodium & chlorine becomes EX: NaCl – sodium & chlorine becomes

sodium chloride; sodium chloride;

MgO – magnesium & oxygen becomes MgO – magnesium & oxygen becomes

magnesium oxidemagnesium oxide

CaBrCaBr22 – calcium & bromine becomes – calcium & bromine becomes

calcium bromidecalcium bromide

Binary IONIC COMPOUNDS

Your Turn

Write the compound formula for the ionic compund formed from the pairs of ions below.

Name each compound as well.

1) Na + and F1- 2) Mg 2+ and S 2-

3) Al 3+ and P 3- 4) K + and S 2-

5) Ca 2+ and Cl1- 6) Al 3+ and Se 2-

7) Cu 2+ and F1- 8) Sn 4+ and Cl1-

9) Cr 3+ and O 2- 10) Pb 4+ and O 2-

Pause for “The Criss-Cross Pause for “The Criss-Cross Method”Method”

DemoDemo

Answers to Binary Ionic CompoundsAnswers to Binary Ionic Compounds

1)NaF sodium fluoride1)NaF sodium fluoride2) MgS magnesium sulfide2) MgS magnesium sulfide3) AlP aluminum phosphide3) AlP aluminum phosphide

4) K4) K22S potassium sulfideS potassium sulfide

5) CaCl5) CaCl22 calcium chloridecalcium chloride

6) Al6) Al22SeSe3 3 aluminum selenide aluminum selenide

7) CuF7) CuF22 copper (II) fluoridecopper (II) fluoride

8) SnCl8) SnCl4 4 Tin (IV) chlorideTin (IV) chloride

9) Cr9) Cr22OO33 Chromium (III) oxideChromium (III) oxide

10) PbO10) PbO22 Lead (IV) oxide Lead (IV) oxide

Polyatomic IonsPolyatomic Ions

Polyatomic ions Polyatomic ions ““poly” means many; “atomic” refers to poly” means many; “atomic” refers to

atomsatoms A polyatomic ion is just an ion made of A polyatomic ion is just an ion made of

several atoms rather than just one as several atoms rather than just one as seen earlier.seen earlier.

Polyatomic ions are groups of atoms with Polyatomic ions are groups of atoms with a positive or negative chargea positive or negative charge

Most polyatomic ions are ANIONSMost polyatomic ions are ANIONS

Polyatomic Ions cont.Polyatomic Ions cont.

The names of most polyatomic ions end in –The names of most polyatomic ions end in –ite or –ate, rather than –ide as with single ite or –ate, rather than –ide as with single element ions.element ions.

EXAMPLES:EXAMPLES:

NONO33 1-1- - nitrate - nitrate NONO22 1-1- - nitrite - nitrite

SOSO44 2-2- - sulfate - sulfate SOSO33 2-2- - sulfite - sulfite

POPO44 3-3- - phosphate - phosphate POPO33 3-3- - phosphite - phosphite

What do you notice about the difference in –What do you notice about the difference in –ate ions and –ite ions of the same family?ate ions and –ite ions of the same family?

Ternary compoundsTernary compounds Ternary ionic compounds are just ionic Ternary ionic compounds are just ionic

compounds that have a polyatomic ion.compounds that have a polyatomic ion. Just like binary compounds the charges Just like binary compounds the charges

must balance.must balance. EX: Na EX: Na ++ & NO & NO33 1-1- The charges are The charges are

balanced so only one of each ion is needed. balanced so only one of each ion is needed. The formula is NaNOThe formula is NaNO33 and is named sodium and is named sodium nitratenitrate

NaNa++ & SO & SO33 2-2- To balance charges, 2 sodium To balance charges, 2 sodium ions are needed. The formula is Naions are needed. The formula is Na22SOSO33 and and is named sodium sulfiteis named sodium sulfite

Ternary Compounds ContTernary Compounds Cont.. It is important to note that the names It is important to note that the names

of polyatomic ions do of polyatomic ions do NOTNOT change. change. Nitrate, nitrite, sulfate etc. tells you Nitrate, nitrite, sulfate etc. tells you which ion you are dealing with.which ion you are dealing with.

Also polyatomic ion formulas Also polyatomic ion formulas DO NOTDO NOT change. NOchange. NO33 for nitrate must stay NO for nitrate must stay NO33 regardless, so what if you need 2 regardless, so what if you need 2 groups of NOgroups of NO3 3 to form a compound?to form a compound?

IF more than one group of a IF more than one group of a polyatomic ion is needed to form a polyatomic ion is needed to form a compound, parentheses are used. compound, parentheses are used. Continue for examples.Continue for examples.

Examples of ternary compoundsExamples of ternary compounds

Mg Mg 2+2+ & NO & NO33 1- 1- Mg(NOMg(NO33))22 Magnesium nitrate Magnesium nitrate

Al Al 3+3+ & ClO & ClO44 1-1- Al(ClOAl(ClO44)) aluminum chloratealuminum chlorate

Al Al 3+ & 3+ & SOSO33 2-2- AlAl22(SO(SO33))33 aluminum sulfitealuminum sulfite

You Try :You Try :

Ca Ca 2+2+ & ClO & ClO33 1-1- Pb Pb 4+4+ & PO & PO44 3-3-

Cu Cu 2+2+ & (NO & (NO22) ) 1-1- Cr Cr 3+3+ & OH & OH 1-1-

Complete the compound Complete the compound writing worksheet writing worksheet