2. VOCABULARY
• ATOMIC THEORY: ___ The idea that
everything is made of small particles.
• ATOM: ___ The smallest part of an element
that still has the properties of the element.
• COMPOUND: ___ A type of matter made of
two or more elements.
• MOLECULE: ___ The smallest particle of a
compound that still has the properties of that
compound.
6. ELEMENT
A substance that cannot be broken down into
simpler substances by chemical means.
OR
An element is a substance that cannot be broken
down into simpler components by any non-
nuclear chemical reaction.
7. ABOUT ELEMENTS
• We have thousands of materials around us,
which are made of same basic kinds of matter,
called ELEMENTS.
• All the substances are made of elements.
• More than 103 different elements have been
discovered till now.
• An element is composed of atoms that have the
same atomic number, that is, each atom has the
same number of protons in its nucleus as all
other atoms of that element.
8. PROPERTIES OF ELEMENTS
• Elements cannot be broken down into other
substances with ordinary physical or chemical
processes.
• Each element has its own specific physical &
chemical characteristics.
• Elements react with other elements
according to their characteristic behavior &
atomic structure.
9. PERIODIC TABLE
• Scientists have arranged the discovered
elements in a “periodic table” according to
their increasing “mass number”.
10. PERIODIC TABLE
A table of the chemical elements arranged in
order of atomic number, usually in rows, so
that elements with similar atomic structure
(and hence similar chemical properties)
appear in vertical columns.
12. PERIODIC TABLE
Periodic table has groups & periods.
PERIODIC TABLE
GROUPS PERIODS
(Vertical columns) (Horizontal rows)
8 groups 7 periods
13. ELEMENTS
Elements can be mainly grouped into
following kinds:
ELEMENTS
METALS NONMETALS
(2/3 of the elements) (1/3 of the elements)
14. DIFFERENTIATIVE PROPERTIES OF
METALS & NONMETALS
METALS
• 2/3 of elements are
metals.
• Have shiny &
lustrous surface
when freshly cut.
• Smooth surface.
• Good conductors of
heat & electricity.
NONMETALS
• 1/3 of elements are
non-metals.
• Have dull & mostly
dark surface.
• Rough surface.
• Bad conductors of heat
& electricity.
15. METALS
• MALLEABLE, means that
these can be shaped into
sheets.
• DUCTILE, means that these
can be shaped into wires.
• Most are solids at room
temperature, except
Mercury.
• EXAMPLES: Calcium,
Aluminium, iron, Copper,
Sodium, Mercury
NONMETALS
DIFFERENTIATIVE PROPERTIES OF
METALS & NONMETALS
•Cannot be shaped into sheets.
•Cannot be shaped into wires.
•Most are gases, few are liquids
or solid.
•EXAMPLES: Silicon, Sulfur,
Carbon, Oxygen, Chlorine,
Neon.
16. SYMBOLS
• Symbols are the short or abbreviated names
of “elements” taken from their first or first
and second letter of their English , Latin or
Greek names.
17. SYMBOLS OF FIRST 20 ELEMENTS
ELEMENT
ELEMENT SYMBOL
HYDROGEN H
HELIUM He
LITHIUM Li
BERYLLIUM Be
BORON B
CARBON C
NITROGEN N
OXYGEN O
FLUORINE F
NEON Ne
SODIUM Na
MAGNESIUM Mg
ALUMINUM Al
SILICON Si
PHOSPHORUS P
SULFUR S
CHLORINE Cl
ARGON Ar
POTASSIUM K
CALCIUM Ca
18. EXAMPLES OF SYMBOLS TAKEN FROM
THEIR ENGLISH NAMES
ELEMENT SYMBOL
HYDROGEN H
HELIUM He
ALUMINIUM Al
CARBON C
CHLORINE Cl
CALCIUM Ca
COPPER Cu
SULFUR S
SILICON Si
OXYGEN O
NITROGEN N
NEON Ne
BROMINE Br
19. EXAMPLES OF SYMBOLS TAKEN FROM
THEIR GREEK OR LATIN NAMES
ELEMENT SYMBOLS
SODIUM Na
POTTASIUM K
IRON Fe
SILVER Ag
TIN Sn
GOLD Au
MERCURY Hg
20. ATOM
The smallest basic part of an element that
still has the properties of the element is
called an atom.
21. ATOMIC THEORY
“All substances around us is matter, which is
made of different elements and all elements
are made of atoms.” This idea that every
thing is made of small particles is known as
the atomic theory”.
22. BASIC PROPERTIES OF ATOMS
• Atoms cannot be seen with a simple
microscope, but special powerful electronic
microscopes are used to look into an atom.
• The atoms of each element are different from
the atoms of other elements.
26. MASS NUMBER & ATOMIC NUMBER
MASS NUMBER: It is the total number of
protons and neutrons present in the nucleus of
an atom.
• Number of Protons + Number of Neutrons
ATOMIC NUMBER:
• Number of protons present in the nucleus of an
atom.
• Number of Protons
27.
28. ABOUT PARTICLES
Always in an ATOM:
• Atomic Number = Number of Protons
• Number of Protons = Number of Electrons
• Mass Number – Atomic Number = Number of
Neutrons
• Mass of a Proton = Mass of a Neutron
• Mass of an electron is very less
• Positive Charge on a Proton = Negative Charge
on an electron.
• There is no overall charge on an atom.
30. SHELLS
• Shells have different energy levels (1,2,3,4,…)
according to their positions from the nucleus.
• Electrons fill in these shells according to a
general rule.
31. What is the rule for filling
electron shells?
• The innermost shell is filled first.
• This shell (K) can contain a maximum of two
(2) electrons.
• The second shell (L) can hold a maximum of
eight (8) electrons.
• Third shell (M) can hold a maximum of
eighteen (18) electrons.
• When this is filled, electrons go into the fourth
shell (N), which can hold a maximum of thirty
two (32) electrons.
32. GENERAL RULE FOR ELECTRONS TO
FILL IN THE SHELLS
ENERGY LEVEL SHELL MAXIMUM NUMBER OF
ELECTRONS
1 K 2
2 L 8
3 M 18
4 N 32
37. ATOMIC STRUCTURE OF HYDROGEN
• ELEMENT= HYDROGEN
• SYMBOL= H
• MASS NUMBER= 1
• ATOMIC NUMBER= 1
• P = 1
• N = 0
• e = 1
38. ATOMIC STRUCTURE OF HELIUM
• ELEMENT=HELIUM
• SYMBOL=He
• Mass Number=4
• Atomic Number=2
• P = 2
• N = 2
• e = 2
39. ATOMIC STRUCTURE OF LITHIUM
• ELEMENT= Lithium
• SYMBOL= Li
• MASS NUMBER= 7
• ATOMIC NUMBER= 3
• P = 3
• N = 4
• e = 3
40. ATOMIC STRUCTURE OF BERYLLIUM
• ELEMENT= Beryllium
• SYMBOL= Be
• MASS NUMBER= 9
• ATOMIC NUMBER= 4
• P = 4
• N = 5
• e = 4
41. ATOMIC STRUCTURE OF BORON
• ELEMENT= Boron
• SYMBOL= B
• MASS NUMBER= 11
• ATOMIC NUMBER= 5
• P = 5
• N = 6
• e = 5
42. ATOMIC STRUCTURE OF CARBON
• ELEMENT= Carbon
• SYMBOL= C
• Mass Number= 12
• Atomic Number= 6
• P = 6
• N = 6
• e = 6
43. ATOMIC STRUCTURE OF NITROGEN
• ELEMENT= Nitrogen
• SYMBOL= N
• MASS NUMBER= 14
• ATOMIC NUMBER= 7
• P = 7
• N = 7
• e = 7
44. ATOMIC STRUCTURE OF OXYGEN
• ELEMENT= Oxygen
• SYMBOL= O
• Mass Number= 16
• Atomic Number= 8
• P = 8
• N = 8
• e = 8
45. ATOMIC STRUCTURE OF FLUORINE
• ELEMENT= Fluorine
• SYMBOL= F
• MASS NUMBER= 19
• ATOMIC NUMBER= 9
• P = 9
• N = 10
• e = 9
46. ATOMIC STRUCTURE OF NEON
• ELEMENT= Neon
• SYMBOL= Ne
• MASS NUMBER= 20
• ATOMIC NUMBER= 10
• P = 10
• N = 10
• e = 10
47. ATOMIC STRUCTURE OF SODIUM
• ELEMENT= Sodium
• SYMBOL= Na
• MASS NUMBER= 23
• ATOMIC NUMBER= 11
• P = 11
• N = 12
• e = 11
48. ATOMIC STRUCTURE OF CHLORINE
• ELEMENT= Chlorine
• SYMBOL= Cl
• MASS NUMBER= 35
• ATOMIC NUMBER= 17
• P = 17
• N = 18
• e = 17
49. ATOMIC STRUCTURE OF CALCIUM
• ELEMENT= Calcium
• SYMBOL= Ca
• MASS NUMBER= 40
• ATOMIC NUMBER= 20
• P = 20
• N = 20
• e = 20
50. COMPOUNDS
• When atoms of two or more elements join
chemically in a particular ratio/way, they make a
“compound”.
• The compound is not simply a mixture of elements,
but it’s a new substance.
• Each compound has its own properties.
• A compound can be very different from the
elements it is made from .
51. CHEMICAL BOND
• When atoms join they
share electrons.
• When they share
electrons, they form a
“chemical bond”.
• A bond can also be
broken.
52. CHEMICAL REACTION
• When atoms form or
break bonds with each
other, it is called a
“chemical reaction”.
53. MOLECULE
• The smallest particle of a compound that still
has the properties of that compound is called
a “molecule”.
• Changing the number, kind or position of the
atoms in a molecule would result in a
molecule of a different substance.
54. WATER MOLECULE
• A water molecule only
has three atoms.
• A water molecule is
always made up of one
atom of oxygen and two
atoms of hydrogen.
• Adding an extra oxygen
atom would turn a water
molecule into a molecule
of a different substance.
• Oxygen & hydrogen are
gases, which form liquid
water on combining.
57. TABLE SALT (SODIUM CHLORIDE)
• Table salt is made up of
a sodium atom and a
chlorine atom.
• Table salt is different
from its ingredients.
Sodium + Chlorine =
Sodium Chloride
Na + Cl NaCl
58. DIFFERENCES IN THE PROPERTIES
SODIUM
• Soft metal.
• Solid at room temperature.
• It has metallic silver shine.
• It can be cut with a knife.
• Not edible.
• It reacts strongly with
chlorine.
CHLORINE
• Nonmetallic gas.
• Gas at room temperature.
• It is greenish yellow.
• Can’t be cut with a knife.
• Poisonous gas.
• It reacts strongly with
sodium.