7. Atomic Number - 05
Atomic Mass / g mol−¹ - 10.81
Electronic Configuration – {He} 2s²2p¹
Electron Negativity – 2.0
Boron is a shiny, black metalloid.
Metalloids have both the properties of a metal and a
non-metal.
It a poor conductor of electricity at low temperatures
but a great conductor of electricity at high
temperatures.
8. It is a pure substance meaning it is made up of one
type of atom.
It has a high melting point 2453 °C.
It has boiling point 3923 °C.
When it is a solid, boron can be as hard diamonds.
Even though it is very hard, it is still too fragile for
useful purposes.
Boron can combine with oxygen to form boron trioxide
(B2O3).
When it is in powder form, it reacts with hot nitric acid
(HNO3) and hot sulfuric acid (H2SO4).
It also dissolves in molten metal.
9. Atomic Number - 13
Atomic Mass / g mol−¹ - 26.98
Electronic Configuration – {Ne} 3s²3p¹
Electron Negativity – 1.5
Aluminium is soft, lightweight, silvery, metal.
It is a great conductor of electricity.
It has a melting point of 933° C
It has a boiling point 2740°C
10. It is both ductile and malleable.
Ductile means “capable of being pulled into thin
wires”.
Malleable means “capable of being hammered into
thin sheets.
In moist air, it gradually combines with oxygen to
form aluminum oxide.
Reacts with many hot acids and alkalis.
Alkalis is a chemical with the opposite properties of
an acid.
Aluminum also reacts with hot water and in powdered
form, it catches on fire.
11. Atomic Number - 31
Atomic Mass / g mol−¹ - 69.72
Electronic Configuration – {Ar} 4s²4p¹
Electron Negativity – 1.6
Gallium is soft, silvery, shiny metal.
Conductor of electricity.
But unlike a regular metal, it is so soft it can melt in the
palm of your bare hand.
It has a very low melting point at 29.7 °C
Gallium can be cooled really easily into a solid but it can
still be cooled below 29.7 °C without turning into a solid.
12. It has boiling point 2676 degrees Celsius
Gallium can combine with most non-metals at high
temperatures
It reacts to both acids and alkali metal.
13. Atomic Number - 49
Atomic Mass / g mol−¹ - 114.82
Electronic Configuration – {Kr} 4d¹°5s²5p¹
Electron Negativity – 1.7
Indium is a silvery, shiny metal.
Conductor of electricity.
It is so soft, if rubbed on paper, it leaves a mark like
lead.
It generates a brief screech when bent.
It has a melting point of 156.6 °C
14. It has a boiling point of 2075° C.
Even though at really low temperatures, gallium can
still be very soft. This property allows gallium to be
used below the temperatures of Absolute Zero.
15. Atomic Number - 81
Atomic Mass / g mol−¹ - 204.38
Electronic Configuration – {Xe} 5d¹°6s²6p¹
Electron Negativity – 1.8
Thallium is a bluish-white metal.
Thallium resembles lead and can be used like lead too.
It is also soft enough to be cut with a knife.
It can melt fairly easily and has a melting point of
302° C.
It Has a boiling point of 1456° C.
16. Thallium reacts with acids.
It also reacts with oxygen too and when exposed to
air, it forms a thin coating of thallium oxide (TL2O).
17. ATOMIC RADIUS –
B < Al > Ga < In ≈ Tl
IONIZATION ENTHALPY
B > Tl > Ga > Al > In
18.
19. It also know as trihydriboron & borine.
Its Is An Unstable And Highly Reactive Molecule.
its is both an odd molecule and a very strong lewis
acid.
STRUCTURE --
Coordination geometry /Molecular Shape –
TRIGONAL PLANAR
20. Dipole moment = 0 D
Appearance = colourless gas
Hybridisation - sp²
B-H bond length – 119pm
Bond angle - 120°
21. FORMULA –B2H6
It is colorless & highly unstable
It is pyrophoric gas at room temperature with a
repulsively sweet odor.
Other name – boroethane
boron hydride
diboron hexahydride
Coordination geometry - tetrahedral
22. The structure (a) and the typical view of the three-centered two-electron bonds
(b) in diborane B2H6 .
23. the structure of diborane is considered to be electron
deficient, and has been confirmed by IR spectroscopy
and electron diffraction.
the bridging B-H-B unit consists of two three-centered
two-electron bonds.
It also known as banana bonding.
The four terminal B-H bonds are normal covalent
bonds.
Diborane represents the archetypal electron deficient
dimeric compound.
It has 12 valance electron.
8 electron are involved in the terminal hydrogen.
4 electron are involved in bridge bonding.
24. In the absence of a Lewis base the dimeric diborane
(B2H6) is formed. Diborane is generally synthesized by
the reaction if BF3 with a hydride source, such as
NaBH4 or LiAlH4.
25. Hydrolysis of diborane yields boric acid, while
alcoholysis yields the appropriate borate ester,
Diborane reacts with Lewis bases to form the
appropriate Lewis acid-base complex.
26. USES OF DIBORANE
It Has Been Suggested As A Rocket
Propellant And Experimentally Fired But
Not Used In Any In Service Rocket As A
Rubbervulcaniser As A Catalyst For
Hydrocarbon , Polymerization As A Flame
Speed Accelerator And As A Doping Agent
For The Production Of Semiconductors.
27. It Is Also An Intermideate In The Production Of
Highly Pure Boron For Semiconductor Production.
it is also used to coat the walls of tokomaks to reduce
the amount of heavy metal impurities in the plasma.
28. They are commonly known as BORANES
(analogy with the alkanes , hydrocarbons).
REPRESENTED BY -
1. NIDO BORANES -- BnHn+6
2. ARACHNO-BORANES-- BnHn+4
2
ND ARE MORE STABLE THAN 1ST
29. A. The Latin prefixes mono-, di-, tri-, etc. are used
before "borane" to indicate the number of boron
atoms in the compound.
B. Immediately following the "e" in "borane" the
number of hydrogen atoms is placed in parentheses
using Arabic numerals.
34. GENERAL FORMULA -- B2X4
THESE DECOMPOSE SLOWLY AT ROOM
TEMPERATURE.
EXAMPLE - B2Cl4
35. BORON FORMS SEVERAL STABLE
POLYMERIC MONOHALIDES (BX)N .
THE COMPOUND B4CL4 , B8CL8 ,B9CL9
ARE CRYSTALLINE SOLIDS.
THEIR STRUCTURE HAVE A CLOSED
CAGE OR POLYHEDRON.
