alkali metals - periodic table

1. DIGITAL ALBUM
on
ALKALI METALS
Presented By
Sreelakshmi A
1st Year B.Ed
Physical Science
GCTE Trivandrum

2. The Periodic Table
• The periodic table of elements,
is a tabular display of the
chemical elements, which are
arranged by atomic number,
electron configuration, and
recurring chemical properties.

4. GROUP 1 ELEMENTS
• The GROUP 1 ELEMENTS in the periodic table
are known as the ALKALI METALS. They are
1. Lithium (Li)
2. Sodium(Na)
3. Potassium(K)
4. Rubidium(Rb)
5. Caesium(Cs)
6. Francium(Fr)

5. ALKALI METALS

6. Alkali metals???
• These metals are called alkali metals because
they form strong alkaline hydroxides(basic in
nature) when react with water.
Examples
1. NaOH
2. KOH
3. LiOH

7. Electronic Configuration
• The general electronic configuration of Group
1 elements is ns1.
• They have a strong tendency to donate their
valence electron in the last shell to form
strong ionic bonds.

9. PROPERTIES
• In order to prevent the elements from coming
in contact with oxygen, they are stored in jars
that contain oil.
• They display a very low level of density of up
to 1 gcm-3 which means that they can easily
float on the surface of the water.
• The melting points of these elements are
quite low, which is 180° Celsius in the case of
Lithium, while it is 39° Celsius in the case of
Rubidium.

11. Change of atomic radius
In alkali metals, the atomic radius increases
down the group. Each element has 1 electron in
each outer shell because they are all in group 1.
Reactivity
The alkali metals are very reactive, but they are
not found in elemental forms in nature. The
elements are usually found in mineral oil, or
paraffin oil. Alkali metals are mostly soft silver-
colored, of low density.

13. Abundance on earth
All of the alkali metals are found in
nature, but not in their pure forms. Most
combine with oxygen and silica to form
minerals in Earth, and have to get
separated from the substance that
they’re combined with. Alkali metals are
soft silver-colored, with low density and
can explode when combined with water.

15. Change of boiling point and melting point
All alkali metals are very soft and they have
low melting and boiling points. Alkali metals
melting and boiling points decrease down the
group, so which means that Lithium has a
lower boiling and melting point than
Francium. As you go down, the alkali metals,
the melting and boiling points get lower.

17. Uses Of Alkali Metals
1. Lithium is used to produce ceramics and glasses.
2. Devices that require batteries, for example mobiles
or computers contain Lithium batteries.
3. Sodium is used to produce salt , in the form of sodium
chloride.
4. Sodium hydroxide is used to clean ovens.
5. Cesium is use to produce military aircrafts.
6. A compound of rubidium, silver and iodine, is used to
make film batteries.
7. Francium doesn’t have many uses, but it’s used in
laboratories for experiments, and needs to be
handled carefully, because it’s toxic.

19. PICTURE WINDOW
ALKALI METALS

20. Lithium ( Li )
Atomic Weight 6.94
Density 0.535 g/cm3
Melting Point 180.54 °C
Boiling Point 1342 °C

21. Discovery
date
1817
Discovered
by
Johan August Arfvedson
Origin of the
name
The name is derived from the Greek 'lithos' meaning stone.
Key
isotopes
7Li

22. Electronic configuration

23. PROPERTIES
• The lightest metal
• Lithium easily floats on water
• Lithium reacts with water releases
hydrogen gas.
• It's soft enough to cut with hand
shears, leaving marks such as you see on
this sample.

24. USES OF LITHIUM
• Lithium is often used in batteries, and lithium
oxide can help process silica.
• Lithium can also be used to make lubricating
greases, air treatment, and aluminum
production.
• Lithium is used for mental illnesses,
including bipolar disorder, depression,
and schizophrenia.

25. Photo sensitive glass from
lithium-silicate family of
glasses
Larger lithium battery.

26. Sodium ( Na )
Atomic Weight 22.98976928
Density 0.968 g/cm3
Melting Point 97.72 °C
Boiling Point 883 °C

27. Discovery
date
1807
Discovered
by
Humphry Davy
Origin of
the name
The name is derived from the English word 'soda'.
Key
isotopes
23Na

28. Electronic configuration

29. PROPERTIES
• These soft.
• Silvery sodium chunks were cut with a knife
and stored under oil.
• In air they turn white in seconds.
• When exposed to water they generate
hydrogen gas and explode in flaming balls of
molten sodium

30. USES OF SODIUM
• Pure sodium has many applications, including use
in sodium-vapor lamps which produce very
efficient light.
• Sodium is used as a heat exchanger in some
nuclear reactors, and as a reagent in the
chemicals industry. But sodium salts have more
uses than the metal itself.
• The most common compound of sodium is
sodium chloride (common salt).
• Sodium carbonate (washing soda) is also a useful
sodium salt. It is used as a water softener.

31. Sodium carbonate, Na2CO3, (awashing soda
Sodium chloride (salt) Sodium vapour lamb

32. BIOLOGICAL ROLE
• Sodium is essential to all living things
• Our bodies contain about 100 grams, but we are
constantly losing sodium in different ways so we need
to replace it.
• We can get all the sodium we need from our food,
without adding any extra.
• The average person eats about 10 grams of salt a day,
but all we really need is about 3 grams.
• Any extra sodium may contribute to high blood
pressure..
• Sodium is important for many different functions of the
human body. For example, it helps cells to transmit
nerve signals and regulate water levels in tissues and
blood.

33. Potassium (K)
Atomic Weight 39.0983
Density 0.856 g/cm3
Melting Point 63.38 °C
Boiling Point 759 °C

34. Electronic configuration

35. PROPERTIES
• The purple tint on these soft potassium cubes
is a very thin oxide coating.
• Exposed to air they turn black in seconds.
• Exposed to water they would explode, sending
off characteristic purple-red flaming drops.

36. USES OF POTASSIUM
• Potassium is important for plant growth. Industrial
applications for potassium include soaps, detergents, gold
mining, dyes, glass production, gunpowder, and batteries.
• The greatest demand for potassium compounds is in
fertilizers.
• Potassium salts are of great importance, including the nitrate,
carbonate, chloride, bromide, cyanide and sulfate.
• Potassium carbonate is used in the manufacture of glass.
• Potassium hydroxide is used to make detergent and liquid
soap.
• Potassium chloride is used in pharmaceuticals and saline
drips.

37. .
Potassium based fertilizer
Potassium hydroxide is used for
Making soap

38. BIOLOGICAL ROLES
• Potassium is essential to life. Potassium ions are found in all
cells. It is important for maintaining fluid and electrolyte
balance.
• Plant cells are particularly rich in potassium, which they get
from the soil. Agricultural land, from which harvests are
taken every year, needs to have its potassium replenished
by adding potassium-based fertilisers.
• The average human consumes up to 7 grams of potassium a
day, and stores about 140 grams in the body cells. A normal
healthy diet contains enough potassium, but some foods
such as instant coffee, sardines, nuts, raisins, potatoes and
chocolate have above average potassium content.
• The naturally occurring isotope potassium-40 is radioactive
and, although this radioactivity is mild, it may be one
natural cause of genetic mutation in humans.

39. RUBIDIUM ( Rb
Atomic Weight 85.4678
Density 1.532 g/cm3
Melting Point 39.31 °C
Boiling Point 688 °C

40. Discovery
date
1861
Discovered by Gustav Kirchhoff and Robert Bunsen
Origin of the
name
The name is derived form the Latin 'rubidius', meaning deepest red.
Key isotopes 85Rb, 87Rb

41. Electronic Configuration

42. PROPERTIES
• This ampoule contains a gram of highly
reactive rubidium metal.
• Broken open it would catch fire rapidly.
• Rubidium is commonly used in cheaper atomic
clocks (the most accurate ones use cesium).

43. USES OF RUBIDIUM
• Rubidium is little used outside research. It has been used as
a component of photocells, to remove traces of oxygen
from vacuum tubes and to make special types of glass.
• It is easily ionised so was considered for use in ion engines,
but was found to be less effective than caesium.
• It has also been proposed for use as a working fluid for
vapour turbines and in thermoelectric generators.
• Rubidium nitrate is sometimes used in fireworks to give
them a purple colour.
• Rubidium carbonate is applied in glass lenses built in night
vision devices.

44. BIOLOGICAL ROLE
• Rubidium has no known biological role and is
non-toxic. However, because of its chemical
similarity to potassium we absorb it from our
food, and the average person has stores of
about half a gram.
• It is slightly radioactive and so has been used
to locate brain tumours, as it collects in
tumours but not in normal tissue.

45. Ceasium (Cs)
Atomic Weight 132.90545196
Density 1.879 g/cm3
Melting Point 28.44 °C
Boiling Point 671 °C

46. Discovery
date
1860
Discovered
by
Gustav Kirchhoff and Robert Bunsen
Origin of the
name
The name comes from the Latin 'caesius', meaning sky blue, and
derived from its flame colour.
Key
isotopes
133Cs

47. Electronic Configuration

48. PROPERTIES
• The cesium in this ampoule melts if you hold it
in your hand for a minute, yielding the
prettiest liquid gold.
• If the ampoule were to break in your hand,
the resulting explosion would be extremely
unpleasant.

49. USES OF CAESIUM
• The most common use for caesium compounds is as a
drilling fluid.
• They are also used to make special optical glass, as a
catalyst promoter, in vacuum tubes and in radiation
monitoring equipment.
• One of its most important uses is in the ‘caesium clock’
(atomic clock). These clocks are a vital part of the
internetand mobile phone networks, as well as Global
Positioning System (GPS) satellites. They give the
standard measure of time: the electron resonance
frequency of the caesium atom is 9,192,631,770 cycles
per second. Some caesium clocks are accurate to 1
second in 15 million years.

51. A caesium atomic fountain used as part of an atomic clock
Caesium formate used as
a drilling and completion fluid.
Autoradiograph of radioactive
cesium particle.

52. Francium (Fr)
Atomic Weight 223
Density Unknown
Melting Point 21°C
Boiling Point 650°C

53. Discovery
date
1939
Discovered by Marguerite Perey
Origin of the
name
Francium is named after France.
Key isotopes 223Fr

54. Electronic Configuration

55. PROPERTIES
• Uranium and thorium minerals produce
francium in vanishingly small quantities via
their natural radioisotope decay chains.
• At most a few atoms at a time exist in a rock
like this, and you can't see any of them.
• Francium has no uses, having a half life of only
22 minutes.
• Francium has no known biological role. It is
toxic due to its radioactivity.