4.3 GROUP PROPERTIES OF ELEMENTS (GROUP 3)

GROUP IIIA - BORON GROUP

• Sometimes termed as “Metalloid” 

• Readily oxidized when heated in air; reacts with sulfur & hydrogen 

• Hydroxides tends to show amphoteric properties

GROUP IIIA - BORON GROUP

• ELEMENTS

• Boron 

• Aluminum 

• Gallium 

• Thalium

Boron (B)

• Physical properties

Appears in 3+ oxidation state

Boron (B)

• industrial use

In vulcanizing rubber 

Boric Acid (H₂BO₃)

• aka

sal sativum

Boric Acid (H₂BO₃)

• toxicity

lobster appearance

Boric Acid (H₂BO₃)

• Used for Buffer (Ophthalmic solution 2%)

• Antiseptic 

• Tonicity adjusting agent

Sodium Borate (Na₂B₄O₇·10H₂O)

• aka

Borax, Sodium tetraborate, Dobell’s solution 

Sodium Borate (Na₂B₄O₇·10H₂O)

• Antiseptic 

• Eyewash 

• Wet dressing for wounds

Aluminum (Al)

• physical properties

• Most abundant metal 

• 3rd most abundant element

Aluminum (Al)

• source

Cryolite (3NaF . AlF₃) - NaAlF

Aluminum (Al)

• pharmacologic use

• Astringent, antiperspirant, deodorant

• Aluminum foil for burn patient (cover with Al foil to facilitate healing) 

• Has styptic property/ hemostatic agent

Alum

• ammonium salt

[AlNH₄(SO₄)₂ . 12H₂O]

Alum

• potassium salt

[AlK(SO₄)₂ . 12H₂O]

Alum

• Astringent 

• Antiperspirant 

• Deodorant

Aluminum Chloride (AlCl₃ . 6H₂O)

• Astringent 

• Antiseptic 

• Antiperspirant / deodorant

Aluminum Hydroxide Al(OH)₃

• aka

amphojel, cremalin gel

Aluminum Hydroxide Al(OH)₃

• disadvantage

• constipation

• phosphate deficiency

Aluminum Phosphate (AlPO₄)

• aka

phosphagel

Aluminum Phosphate (AlPO₄)

• Antacid 

• Astringent 

• Demulcent

Aluminum Phosphate (AlPO₄)

• advantage

• Do not interfere with Phosphate absorption 

Aluminum Carbonate Al₂(CO₃)₃

Treatment of Phosphatic caliculci

Aluminum Oxide (Al₂O₃)

• aka

alumina

Aluminum Oxide (Al₂O₃)

treatment of silicosis

Aluminum Silicate

• kaolin

• bentonite

• pumice

Kaolin

• aka

Kaolin

adsorbent in diarrhea

Bentonite

• aka

Bentonite

suspending agent

pumice

• volcanic origin

• dental abrasive

Gallium (Ga)

• Melts at near body temp (30°C) 

• Treatment of cancer related hypercalcemia by binding with transferrin

• Used for substitute for mercury in manufacture of arc lamp

Thallium (Tl)

• Highly toxic, highly restricted 

• Green twigs

• Ant poison (insecticide)

GROUP IIIB- SCANDMIUM SUBGROUP

• Exhibit an oxidation state of 2+ and 3+

• Have physical properties that are typically metal

• Oxides are basic

• Quite reactive

GROUP IIIB- SCANDMIUM SUBGROUP

• elements

Scandium (Sc) / EKA BORON

Yytrium (Y)

Lanthum

Actinum

Lanthanide (La-Lu; 57-71)

Actinide (Ac-Ir; 89-103)