CHEMICAL BONDING

• IONIC BONDS

• COVALENT BONDS

IONIC BONDING

When an atom of a nonmetaltakes one or more electrons

from an atom of a metalso both atoms end up with

eight valence electrons

IONIC BONDING

IS THE COMPOUND AN IONIC COMPOUND?

METALMETAL NONMETAL

SUBSCRIPTS

IONIC BOND FORMATION

Neutral atoms come near each other. Electron(s) are transferred from the Metal atom to the Non-metal atom. They stick together because of electrostatic forces, like magnets.

IONIC BONDING

Metals will tend to lose electrons and become

POSITIVE CATIONS

Normal sodium atom loses one electron to become sodium ion

IONIC BONDING

Nonmetals will tend to gain electrons and become

NEGATIVE ANIONS

Normal chlorine atom gains an electron to become a chloride ion

POLYATOMIC IONS--a group of atoms that act like one ion

NH4+1--ammonium ion

CO3-2--carbonate ion

PO4-3--phosphate ion

IONIC BONDING

IONIC BONDING

SODIUM SULFATE

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.

COVALENT BONDING

When an atom of one nonmetal

shares one or more electrons

with an atom of another

nonmetal so both atoms

end up witheight valence electrons

COVALENT BOND FORMATION

When one nonmetal shares one or more electrons with an atom of another nonmetal so both atoms end up with eight valence electrons

COVALENT BONDING

IS THE COMPOUND A COVALENT COMPOUND?

NONMETALNONMETAL NONMETAL

YES since it is made of only nonmetal elementsYES since it is made of only nonmetal elements

Covalent bonding

• Fluorine has seven valence electrons

F

Covalent bonding

• Fluorine has seven valence electrons

• A second atom also has seven

F F

Covalent bonding Fluorine has seven valence electrons A second atom also has seven By sharing electrons

F F

Covalent bonding Fluorine has seven valence electrons A second atom also has seven By sharing electrons

F F

Covalent bonding Fluorine has seven valence electrons A second atom also has seven By sharing electrons

F F

Covalent bonding Fluorine has seven valence electrons A second atom also has seven By sharing electrons

F F

Covalent bonding Fluorine has seven valence electrons A second atom also has seven By sharing electrons

F F

Covalent bonding Fluorine has seven valence electrons A second atom also has seven By sharing electrons Both end with full orbitals

F F

Covalent bonding Fluorine has seven valence electrons A second atom also has seven By sharing electrons Both end with full orbitals

F F8 Valence electrons

Covalent bonding Fluorine has seven valence electrons A second atom also has seven By sharing electrons Both end with full orbitals

F F8 Valence electrons

Single Covalent Bond

• A sharing of two valence electrons.

• Only nonmetals and Hydrogen.

• Different from an ionic bond because they actually form molecules.

• Two specific atoms are joined.

• In an ionic solid you can’t tell which atom the electrons moved from or to.

Water

H

O

Each hydrogen has 1 valence electron

Each hydrogen wants 1 more

The oxygen has 6 valence electrons

The oxygen wants 2 more

They share to make each other happy

Water

• Put the pieces together• The first hydrogen is happy• The oxygen still wants one more

H O

Water

• The second hydrogen attaches

• Every atom has full energy levels

H OH

CovalentBonds

LET’SFIRSTREVIEWIONICBONDING

In an IONIC bond,electrons are lost or gained,resulting in the formation of IONS

in ionic compounds.

FK

FK

FK

FK

FK

FK

FK

FK+ _

FK+ _

The compound potassium fluorideconsists of potassium (K+) ions

and fluoride (F-) ions

FK+ _

The ionic bond is the attractionbetween the positive K+ ion

and the negative F- ion

Sowhatarecovalentbonds?

In covalent bonding,atoms still want to achievea noble gas configuration(the octet rule).

In covalent bonding,atoms still want to achievea noble gas configuration(the octet rule).

But rather than losing or gainingelectrons,atoms now share an electron pair.

In covalent bonding,atoms still want to achievea noble gas configuration(the octet rule).

But rather than losing or gainingelectrons,atoms now share an electron pair.

The shared electron pairis called a bonding pair

Cl2

Chlorineforms

acovalent

bondwithitself

ClClHowwilltwochlorineatomsreact?

ClClEach chlorine atom wants to gain one electron to achieve an octet

ClClNeither atom will give up an electron –chlorine is highly electronegative.

What’s the solution – what can theydo to achieve an octet?

ClCl

Cl Cl

Cl Cl

Cl Cl

Cl Cloctet

Cl Cl

circle the electrons foreach atom that completestheir octets

octet

Cl Cl

circle the electrons foreach atom that completestheir octets

The octet is achieved byeach atom sharing theelectron pair in the middle

Cl Cl

circle the electrons foreach atom that completestheir octets

The octet is achieved byeach atom sharing theelectron pair in the middle

Cl Cl

circle the electrons foreach atom that completestheir octets

This is the bonding pair

Cl Cl

circle the electrons foreach atom that completestheir octets

It is a single bonding pair

Cl Cl

circle the electrons foreach atom that completestheir octets

It is called a SINGLE BOND

Cl Cl

circle the electrons foreach atom that completestheir octets

Single bonds are abbreviatedwith a dash

Cl Cl

circle the electrons foreach atom that completestheir octets

This is the chlorine molecule,

Cl2

O2

Oxygen is also one of the diatomic molecules

How will two oxygen atoms bond?

OO

OOEach atom has two unpaired electrons

OO

OO

OO

OO

OO

OO

Oxygen atoms are highly electronegative.

So both atoms want to gain two electrons.

OO

Oxygen atoms are highly electronegative.

So both atoms want to gain two electrons.

OO

OO

OO

OO

OO

OOBoth electron pairs are shared.

6 valence electronsplus 2 shared electrons

= full octet

OO

6 valence electronsplus 2 shared electrons

= full octet

OO

two bonding pairs,

OOmaking a double bond

OO=For convenience, the double bond

can be shown as two dashes.

OO

OO=This is the oxygen molecule,

O2

this is so

cool!!