Elements are pure substances that cannot be broken down further by chemical reactions or processes. They consist of only one type of atom and exist as either individual atoms or molecules made of atoms of the same element. Compounds are pure substances made of two or more elements chemically bonded together in fixed ratios. Compounds have distinct properties and can be broken down into their constituent elements. Mixtures are physical combinations of elements or compounds not chemically bonded. They do not have a fixed composition and their properties depend on the substances that make them up. Mixtures can be separated into their components using physical processes like filtration or evaporation.

1. Done by -
Debjani Purkayastha

2. Lesson Objective
 Elements
Compounds
 Mixtures

3. An Overview
MATTER
PURE SUBSTANCES
COMPOUNDS
HOMOGENEOUS
ELEMENTS
HETEROGENEOUS
MIXTURES

4. Introducing Little Miss
“Element”
 *Chemical process refers to chemical reaction or
heat
 **Electricity refers to electrolysis
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**!

5. Elements
Definition 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.

6. Elements
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).

7. Examples of elements
 Elements are made up of tiny particles
 Elements can be further classified into two groups:
Atoms Molecules
Is the smallest
particle
of an element and has
the same chemical
properties of the
element
Is made up of two or
more atoms that are
chemically bonded
together.
(note: these atoms are
of the
SAME element!!)

8. T h e s e A r e E l e m e n t s
 Atoms of same element
Helium Copper Sodium
 Molecules of same element
Hydrogen gas element Ozone
He Cu Na
H
H
O
O
O

9. Atoms Elements
An element is made of
tiny particles
called atoms.
The atoms of an
element is different
from that of another
element.
Consists of
only one kind
of atom

10. Molecules
 Very 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.
 Molecules consisting of a few atoms are called
polyatomic molecules.
 For example Hydrogen (H2) is a diatomic molecule.
Ozone (O3) is a triatomic molecule.

11. Chemical Symbols of
Elements
 Chemists use symbols to represent elements.
 For example, O represents oxygen while Fe
represents iron.
Element Symbol
Calcium Ca
Hydrogen H
Iron Fe
Carbon C
Mercury Hg
Neon Ne
Sodium Na

12. Classification of Elements –
Metals and Non-metals
 There are two major groups of elements – metals
and non-metals.
 Iron is a metal. Oxygen is a non-metal.
 Metals and non-metals are grouped separately on
the Periodic Table.
 There are some elements called metalloids which
behave like both metals and non-metals.

13. P r o p e r t i e s

Metals Non -metals
Shiny appearance Dull appearance
Solids at r.t.p (except mercury) Gases, liquids or solids at
room temp & pressure
High melting and boiling points
Low melting and boiling points
Malleable, Ductile, Sonorous Brittle if solid (general)
Good conductors of heat Poor conductors of heat
Good conductors of electricity Poor conductors of electricity
(expect carbon and graphite)

14. Metals Non – metals Metal
which exhibit the
gree of metallic
s known as metals
Non-metals are such elements
which do not possess any metallic
behaviour.
Metalloids are s
which posses
properties like m
like non
ced on the left side of
riodic table.
Non-metals are placed on the right
side of the periodic table
Metalloids are pla
of the perio
a shiny appearance. Non-metals have a dull appearance. Metalloids have
appear
ectrical conductivity
h in metals.
It is very low in non-metals. Thermal and elect
is good though it is
w electronegativity. Non-Metals have high
electronegativity.
Metalloids neith
high or too l
electrone
ow ductility and
lleability.
Non-metals do not show ductility
and malleability.
Metalloids also d
prop
odium,Calcium,
arium, Lead, Indium,
on, Copper, Zinc,
Iodine, Bromine, Helium, Neon,
Argon, Krypton, Sulfur,
Phosphorous, etc.
Arsenic, Telluri
Polonium, Ten

15. Introducing Little Mr “Compounds”
I am also a PURE
SUBSTANCE
I am made up of
a fixed number
of two or more
elements
chemically
combined.

16. Compound
 Note 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.

17. What is a compound ?
 A compound is a substance which is made up of two or
more elements chemically combined together.
Water Ammonia
Consists of two or more elements And They are chemically combined
together!
H
O
H H
N
H
H

18. Little Mr “Compound” Property
I am formed by atoms
of different elements.
However, I do not
have the properties
as them.
Examples
• Na + Cl2  NaCl
(s) (g) (s)
• H2 + O2  H2O
(g) (g) (l)

19. Fixed Composition of
Compounds
 For example, water (H2O) is a compound made only by
joining together two atoms of hydrogen to one atom of
oxygen.
 That is, the ratio of hydrogen atoms to oxygen atoms
in water is always 2 : 1.
A compound is made up of different elements chemically
combined in a fixed ratio.

20. Various types of separation processes are:
 Using a separating funnel:
 A separating funnel is used for the separation of components of a
mixture between two immiscible liquid phases. One phase is the
aqueous phase and the other phase is an organic solvent. This
separation is based on the differences in the densities of the
liquids. The liquid having more density forms the lower layer and
the liquid having less density forms the upper layer.
 Applications:
To separate a mixture of oil and water.
To separate a mixture of kerosene oil and water.

21. Simple distillation:-
 Simple distillation is a method used for the separation of
components of a mixture containing two miscible liquids that
boil without decomposition and have sufficient difference in
their boiling points.
 Applications:
Separation of acetone and water.
Distillation of alcohol.

23. Decantation
 Decantation is a process to separate mixtures by
removing a liquid layer that is free of a precipitate, or the
solids deposited from a solution. The purpose may be to
obtain a decant (liquid free from particulates) or to recover
the precipitate.

24. Sublimation
Sublimation is the
transition of a substance
directly from the solid
to the gas state, without
passing through the
liquid state.

25. Evaporation
 Evaporation is a type of
vaporization that occurs on the
surface of a liquid as it changes
into the gas phase. The
surrounding gas must not be
saturated with the evaporating
substance. When the molecules
of the liquid collide, they
transfer energy to each other
based on how they collide with
each other.

26. Magnetic separation
 Magnetic separation is
the process
of separating componen
ts of mixtures by
using magnets to
attract magnetic materi
als. The process that is
used for magnetic
separation detaches
non-magnetic material
with those who
are magnetic.

27. Filtration
 Filtration is a physical, biological or chemical operation
that separates solid matter and fluid from a mixture with a
filter medium that has a complex structure through which
only the fluid can pass.

28. Gravity separation
 Sand and sawdust can
be separated by gravity method. ... Mix sand and saw
dust in water saw dust being lighter will float on water,
and sand being heavier gets settled at bottom due
to gravitational force of attraction.

29. Hand Picking
 The method in which substances in a mixture can be
separated by just picking them out with the help
of hand from the mixture is known
as handpicking method. It is one of the various methods
which are carried out in dry conditions.

30. Molecules
 A molecule consists of two or more atoms of
the same element, or different elements, that are
chemically bound together.
 It can be a molecule of an element
E.g. N2, O2, S8
 It can be molecule of a compound.
H2O, CO2, NH3

31. Introducing Little Mr. “Mixture”
I am formed when two or more
substances joined together physically
(without chemical bonds)
I have the same properties as all the
substances

32. Mixtures
 Definition 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.
 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.
 Examples of mixtures include muddy water and air.
 Air is made up of gases such as nitrogen and oxygen mixed
together.

33. Little Mr “Mixture”
I do not have a fixed
composition
of the substances.
A Mixture can be:
• element + element
• element + compound
• compound + compound.
He can be separated to
its
substances by physical
methods

36. Thank you
This is the end of the slide.