WHAT IS CHEMISTRY?WHAT IS CHEMISTRY?

Is a basic science evolved from the medieval practice of alchemy.

Its foundations were Boyle, Avogadro, Lavoisier, Dalton and other.

Chemistry has to study:Chemistry has to study:

The structure and behaviour of atoms;

Compositions and properties of compounds;

Reactions between substance end their energy exchange;

Why elements have some characteristic.

There are two branches of There are two branches of chemistry:chemistry:

INORGANIC CHEMISTRY

Examines differences between all the different kind of atom;

Study all substance except Hydrocarbons and their derivates.

ORGANIC CHEMISTRY

Study all compounds of carbon except :

•Binary compounds: carbon oxides;

•Ternary compounds: metallic cyanides

•Metallic carbonates: calcium carbonate, sodium carbonate

CLASSIFICATION OF MATTERCLASSIFICATION OF MATTER

STATES OF MATTERSTATES OF MATTER

SolidSolid LiquidLiquid Gas Gas

Copyright © 2005 by Pearson Education, Inc.Publishing as Benjamin Cummings

The representation of the The representation of the elementselements

First letter of its name and another letter

Carbon CCalcium CaCobalt CoChlorine ClChromium Cr

Latin name

Sodium(Natrium) NaCopper(Cuprum) CuIron(Ferrum) Fe

Periodic Table of Elements Periodic Table of Elements

What’s in a square?What’s in a square?

Different periodic tables can include various bits of information, but usually:

atomic number symbol atomic mass number of valence

electrons state of matter at room

temperature.

FamiliesFamilies Columns of elements are

called groups or families. Elements in each family

have similar but not identical properties.

For example, lithium (Li), sodium (Na), potassium (K), and other members of family IA are all soft, white, shiny metals.

All elements in a family have the same number of valence electrons.

PeriodsPeriods Each horizontal row of

elements is called a period.

The elements in a period are not alike in properties.

In fact, the properties change greatly across even given row.

The first element in a period is always an extremely active solid. The last element in a period, is always an inactive gas.

Properties of MetalsProperties of Metals Good conductors of

heat and electricity. Shining. Ductile (can be

stretched into thin wires).

Malleable (can be pounded into thin sheets).

Reacts with the air, this reactions is called corrosion.

To preserve metal from corrosion we can keep air away from the metal or change its properties by making alloy:a mixture of 2 or more metal.

They are mixed when they are in liquid form and then they are made to cool and solidfy.

Properties of Non-MetalsProperties of Non-Metals• Non-metals are poor

conductors of heat and electricity.

• Non-metals are not ductile or malleable.

• Solid non-metals are brittle and break easily.

• They are dull.• Many non-metals are

gases.

Properties of MetalloidsProperties of Metalloids• Metalloids (metal-like)

have properties of both metals and non-metals.

• They are solids that can be shiny or dull.

• They conduct heat and electricity better than non-metals but not as well as metals.

• They are ductile and malleable.

THE ENDTHE END

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