01 Track 1.wma

Chemical Bondingdownload this presentation fromhttp://mrged.flexinet.com.au

You should know all of this!!!

1. the structure of the first 20 elements

2. The special stability of the inert gases

3. Why the other elements take part in chemical reactions

4. The unreactive metals silver, gold and copper

5.The reactions of Group 1 and 7 elements

This morning we shall,1. Find out about the two main types of chemical bonding

2. Start to write some chemical formulas

(formulae)

The Periodic Table

Reactive Metals Non Metals Inert GasesHydrogenWeak Metals

Transition MetalsF Block Metals

Element Types

Group 7The HalogensReactiveNon-metals

7 OE

Group 0The Inert Gases

DO NOT REACT

Full Orbits

Group 1+ 2 metals

Are the most reactive metals known

1 0r 2 OE

atomic + mass numbers

electron arrangements and orbits

The structures of the first 20 elements

???

Atom structuresrevised

Fluorine F19

9

ClF(2,7)

Potassium K K39

19

(2,8,8,1)

BASIC CONCEPT!

ALL ATOMS WANT TO FIND A WAY OF FILLING THE OUTER ORBIT.

Why do chemical reactions take place?

The inert gases are completely stable and DO NOT take part in chemical reactions

Atoms of other elements take part in chemical reactions so that they can become more stable. They would all like to have the same electron arrangements as the inert gases.

They can do this by either transferring electrons completely

or

by sharing electrons

Types of chemical bonding.

Ionic BondingThis type of bondingwill occur when a metal reacts with a non -metal

It always involves a complete transfer of electrons

It always produces IONS (charged particles)

Mg O

12 protons12 electrons12 neutrons

8 protons8 electrons8 neutrons

Mg atomoxygen atom

no overall chargeno overall charge

Mg O

The product particles12 protons10 electons12 neutrons

8 protons10 electrons8 neutrons

Magnesium ion

oxide ion

+2 charge

-2 charge

1 Mg reacts with 1 O atom formula = MgO

Mg

12 protons12 electrons12 neutrons

9 protons9 electrons10 neutrons

Mg atomfluorine atom

no overall chargeno overall charge

ClF

How will magnesium react with fluorine?

Mg

12 protons12 electrons12 neutrons

9 protons9 electrons10 neutrons

Mg atom

fluorine atom

will become +2

will become -1

ClF

Two fluorine atoms are required

Cl

1 Mg reacts with 2 F.............Formula = MgF2

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1 Na reacts with 1 Cl Formula = NaCl

How ionic substances like NaCl dissolve in water

Covalent BondingThis type of bondingwill occur when a non- metal reacts with a non -metal

Here both atoms will share electrons

It always produces molecules (particles with no charge)

H

O

H

Water, the most important compound on the planet

Contains two non-metals

Both require electrons

Both share!

This is covalent bonding

HO

H

HO

H

Covalent bonds here

H

H

H

Ammonia

N

H

H

H

Ammonia

N

H

H

H

Ammonia

N

Contains 3 covalentbonds

In this section we will find out how to write chemical FORMULAE

Student guide to writing chemical formulae

;

Rules leading to correct formulaP

lease copy into your exercise books

1. Positive ions (cations) can join to negative ions (anions)

2. Positive ions usually form the first part of the name (99% cases)

3. If the formula is correct there is no overall charge

4. If you have more than one polyatomic ion it is placed inside brackets

Essential training ions

Positive ions(Cations)

Negative ions(Anions)

+ 1 - 1

+2 - 2

+3 - 3

sodium Napotassium K

hydrogen H

lithium Lisilver Ag

fluoride F chloride Clbromide Br hydroxide OH

nitrate NO3

hydrogencarbonate HCO3

magnesium Mgcalcium Ca

barium Bazinc Zniron(11) Fe

copper Cu

carbonate CO3oxide Osulphide S

sulphate SO4sulphite SO3

chromate CrO4

aluminium Al

chromium Cr

iron(111) Fe

nitride Nphosphate PO4

ammonium NH4

Chemical Formulae 1.

CHARGESIONS NUMBERS

FORMULA

sodium fluoride

Na

F

Chemical Formulae 2.

CHARGESIONS NUMBERS

FORMULA

magnesium fluoride

Mg

F

Chemical Formulae 3.

CHARGESIONS NUMBERS

FORMULA

silver hydroxide

Ag

OH

Chemical Formulae 4.

CHARGESIONS NUMBERS

FORMULA

calcium nitrate

Ca

NO3

Chemical Formulae 5.

CHARGESIONS NUMBERS

FORMULA

ammonium carbonate

Chemical Formulae 6.

CHARGESIONS NUMBERS

FORMULA

aluminium bromide

Chemical Formulae 7.

CHARGESIONS NUMBERS

FORMULA

chromium sulphide

Chemical Formulae 8.

CHARGESIONS NUMBERS

FORMULA