CLASSIFICATION OF MATTER

VIJITHA V.

PHYSICAL SCIENCE

N.S.S.T.C PANDALAM

REG NO: 13304020

Elements, Compounds and Mixtures

“ single, attached, play play…”

Introducing Little Miss “Element”

Hi! I am Little Miss “Element”I am PURE SUBSTANCE

I cannot be broken down into any simpler substance by

means of a chemical reaction* or electricity**!

*Chemical process refers to chemical reaction or heat

**Electricity refers to electrolysis

ElementsDefinition of an element:

An element is a pure substance which cannot be split up into two or more

simpler substances by chemical means.

Sugar is not an element as it can be broken down into carbon and water.

Note that an element:

• Consists of only one kind of atom,

• Cannot be broken down into a simpler type of matter by either physical or chemical means

• Can exist as either atoms (e.g. argon) or molecules (e.g., nitrogen).

Elements

Examples of elementsElements are made up of tiny particles

Elements can be further classified into two groups:

Is the smallest particle of an element and has

the same chemical propertiesof the element

Is made up of two or moreatoms that are chemically

bonded together

(note: these atoms are of the SAME element!!)

Hi, I am from the “Noble gas” family and I work alone

We same

same!!

These are elements!

Atoms of same element

Cu

copper element

Na

sodium element

He

helium element

Molecules of same element

HHydrogen gas element

O

H

OO

ozone

AtomsAn element is made of tiny particles called atoms.

The atoms of an element is different from that of another element.

What is an atom?Examples of models of atoms:

H Na Cl

Hydrogen atom

Sodium atom

Chlorine atom

MoleculesVery few elements exists as

atoms besides elements such

as helium and neon.

Most elements exist as

molecules.

For example, hydrogen

is H2.

Ozone is O3.

Hydrogen (H2) is a

diatomic molecule.

Ozone (O3) is a

triatomic molecule.

Molecules consisting of a

few atoms are called

polyatomic molecules.

Examples of molecules (elements)

H H

N N

O

O

O

O O S

SS

SS

S

SS

Chemical Symbols of Elements

Chemists use symbols to represent elements.

For example, O represents oxygen while Fe represents iron.

Element Symbol Element Symbol

Calcium Ca Mercury Hg

Carbon C Neon Ne

Hydrogen H Silicon Si

Iron Fe Sodium Na

Introducing Little Miss “Compounds”

Harlow! Hehee!!!*giggles*

I am also a PURE SUBSTANCEI am made up of a fixed number

of two or more elements chemically combined.

CompoundsNote that a compound:

• can be broken down into a simpler type of matter (elements) by chemical means (but not by physical means),

• has properties that are different from its component elements, and

• always contains the same ratio of its component atoms.

A compound is a substance which is made up of two or more elements chemically combined together.

What is a compound?

- Chemical reactions taking place.

Qn: Is this a compound?

It only contains one type of element.

Qn: Is this a compound?

It only contains one type of element.

H

O

HO

O

Qn: Is this a compound?

It is not chemically combined.

So, what is a compound then?

H

Water Ammonia gas

Consists of two or more elements

And

They are chemically combined together!

ELEMENTSCOMPOUNDhydrogen

(colourless gas)

oxygen(colourless

gas)

lighted splint

heat, light and

explosion

water(colourless

liquid)

Making compounds from their elementsExample: Making water (picture)

Water molecule

Oxygen molecule

Hydrogen molecule

mixture of

hydrogen and

oxygen

water

Example: Making water (models)

heat, light and

explosion

Making compounds from their elements

Example: Making iron sulphide compound

Iron + sulphur iron sulphide

elementscompound

+

yellow grey

heat

heat

black

Summarizing• A compound is made up of two or more

elements chemically joined together• A compound has a fixed composition• Every compound has a unique chemical

formula• A compound has a completely different

properties from its elements• A chemical reaction (decomposition or

electrolysis) is needed to separate the elements in the compound

Think about this…ROJAK!!

Introducing Little Mr. “Mixture”

Burp!!!! I am messy!

I am formed when two or more substances joined together physically (without chemical

bonds)

I have the same properties as all the substances

AIR

I am his best friend!

MixturesDefinition of a mixture:

A mixture is not a pure substance as it contains a mixture of atoms of

molecules which are not chemically combined together.

Mixtures• Note that a mixture: • consists of two or more different elements

and/or compounds NOT chemically combined.• Can be homogeneous or non-homogeneous • can be separated into its components by

physical means, and • often retains many of the properties of its

components.

Mixtures

• Examples of mixtures include muddy water and air.

Air is made up of gases such as nitrogen and oxygen mixed together.

Little Mr “Mixture”I do not have a fixed composition of the substances.

A Mixture can be:• element + element

• element + compound• compound + compound

(Refer to page 59, Fig 4.7)

He is a “boo-boo!”

He can be separated to its substances by physical

methods

ConclusionAn element is a pure substance which cannot be

split up into two or more simpler substances by chemical means.

A compound consist of a fixed number of different kinds of atoms chemically combined together.

A mixture is not a pure substance as it contains a mixture of atoms of molecules which are not chemically combined together.

The End……