THE PERIODIC TABLE
2º ESO
NATURAL SCIENCES
Introduction……
o The periodic table represents all of the known elements arranged in
groups according to similar properties.
o Elements are arranged in the table in order of their atomic number.
o Each box contains the symbol, for the element, the name of the element
and
d it´s
i ´ atomic
i number.
b
o The atomic number of the element is the number of protons and the
number
num
er of e
electrons
ectrons in
n the atoms of the element.
e ement.
¡REMEMBER!
The periodic table
contains all of
f the
naturally occuring
and man-made
elements
Hydrogen
y
g
is a
Non-Metal
METALS
NON
METALS
Most
Reactive
Least
Reactive
Alkaline Earth Metals
Boron Elements
Carbon
C
b
Elements
Nitrogen
Elements
Oxygen
O
Elements
Hydrogen
(Example
p 1)
o Hydrogen is the lightest element and can be used as a lifting agent in
balloons.
o Since Hydrogen gas is highly inflammable, it can be dangerous to use.
o This property and others make Hydrogen suitable for use as a fuel.
o The most common use of Hydrogen is in chemical processes and
reactions.
Alkaline Metals
Alkaline Metals have the following properties in common:
oThey have low melting and boiling points compared to most other metals.
metals
oThey
y are very
y soft and can be cut easily
y with a knife.
oThey have low densities (lithium, sodium and potassium will float on water)
oThey react quickly with water, producing hydroxides and hydrogen gas.
oTheir hydroxides and oxides dissolve in water to form alkaline solutions.
solutions
Potassium
Alkaline - Expample 2
Properties
o
o
o
o
o
Soft
Reacts with air
Stored in oil
Silver in colour
Melting point
63.38ºc
o Boiling point 759
759ºc
c
The Transition Elements
The Transition Metals have the following properties in
common:
oThey
y form coloured compounds
p
oThey are good conductors of heat and electricity
oThey can be hammered or bent into shape easily
y are less reactive than alkali metals
m
such as sodium
m
oThey
oThey are usually hard and tough
oThey have high densities
oThey have high melting points
points-but
but mercury is a liquid at room temperature
Gold
Transition Elements – Example 3
Properties
oSoft for a metal
oCan be polished to a high shine
oResistant to corrosion
oGood conductor of electricity
oGood conductor of heat
oMelting point 1064.18
1064.18ºc
c
oBoiling point 2856ºc
Halogen Elements
The Halogen elements have the following properties in
common:
oThe halogens have similar properties
oThey all have seven electrons in the outer shell.
oThey all react very vigorously with alkali metals to form salts.
oHalogen
g means salt g
giver
Chlorine
Halogen Elements – Example 4
Properties
oDiscovered in 1774 by Carl Wilhelm Scheele, who mistakenly
thought it contained oxygen.
oObtained from common salt
oMelting point -101.5
101 5ºC
C
oBoiling point -34.04ºC
The Noble Gases
The Noble Gases have the following
properties in common:
o The noble gases are quite unreactive
o They
hey have low bo
boiling
l ng po
points
nts
o They are gases at room temperature
o You can also
l find small
ll amounts of the Noble
l
gases in the atmosphere.
oHelium, neon and argon form no known
compounds.
Helium
Noble Gases – Example 5
Properties
o Helium has no taste, colour or smell
o The gas is produced in massive stars like the sun where 4
hydrogen atoms fuse together.
o Melting point -272.2ºC
o Boiling
l
point – 268.93ºC
º
o 2nd lightest
g
elemenet
Activity
Photocopy
h
http://www youtube com/watch?v=SmwlzwGMMwc&feature=related
http://www.youtube.com/watch?v=SmwlzwGMMwc&feature=related