Group 3A: The Boron GroupGroup 3A: The Boron Group

BoronBoron AluminumAluminum GalliumGallium

The Boron GroupThe Boron Group

Boron

AluminumGallium

The Boron Group

• Group 3A elements are always found combined with other elements in nature.

• Based on the group number you would expect for group 3A elements to lose 3 valence electrons to form ions with 3+ charge.

• Boron, Aluminum, Gallium, and Indium form such ions, but Thallium does not.

• Thallium is the most metallic member of the group with properties similar to those of alkali metals.

• Gallium and indium can form ions with a 1+ charge.

BoronBoron

Although group 3A is named for metalloid Although group 3A is named for metalloid boron, as with other groups, the lightest boron, as with other groups, the lightest member is the least representative.member is the least representative.

Boron has more in common with silicon Boron has more in common with silicon in group 4A than with the metallic in group 4A than with the metallic members of group 3A.members of group 3A.

The main source of boron is a complex The main source of boron is a complex compound of boron called borax.compound of boron called borax.

Borax is used as a cleaning agent and as Borax is used as a cleaning agent and as fire proof insulation.fire proof insulation.

Boric acid, another compound of boron is Boric acid, another compound of boron is used as a disinfectant and an eyewash.used as a disinfectant and an eyewash.

A form of boron nitride is the second A form of boron nitride is the second hardest known material ; only diamond is hardest known material ; only diamond is harder.harder.

These materials are classified as These materials are classified as superabrasives.superabrasives.

AluminumAluminum Aluminum is the most Aluminum is the most

abundant metal and the third abundant metal and the third most abundant element in most abundant element in earth’s crust.earth’s crust.

Aluminum oxide is the major Aluminum oxide is the major compound in bauxite. It is used compound in bauxite. It is used as an abrasive, to strengthen as an abrasive, to strengthen ceramics, and in heat resistant ceramics, and in heat resistant fabrics.fabrics.

The compound aluminum The compound aluminum sulfate, known as alum, is sulfate, known as alum, is used in antiperspirants and to used in antiperspirants and to remove suspended particles remove suspended particles during water purification.during water purification.

GalliumGallium• Gallium can literally melt in your hand.• A compound of gallium and arsenic called gallium arsenide produces an electric current

when it absorbs light.• This property makes gallium arsenide ideal for the semiconductor chips used in light

powered calculators and solar panels.• Scientist are using a compound of gallium and nitrogen, gallium nitride, to develop lasers

that emit blue rather than red light.• Using the shorter wavelengths of blue light would triple the storage capacity of a DVD.• Metical devices for detecting cancer cells could be less expensive if they use low cost,

blue light lasers.

Quiz!!Quiz!!

What is the main source of Boron?What is the main source of Boron? BoraxBorax What is it used for?What is it used for? Cleaning and fireproof insulationCleaning and fireproof insulation What is the most abundant metal?What is the most abundant metal? AluminumAluminum What is the compound aluminum sulfate used in?What is the compound aluminum sulfate used in? AntiperspirantsAntiperspirants What is a compound of gallium and nitrogen, and What is a compound of gallium and nitrogen, and

gallium and nitride used to make?gallium and nitride used to make? Lasers that emit blue lightLasers that emit blue light