4.8 GROUP PROPERTIES OF ELEMENTS (GROUP 8)

GROUP VIIIA - NOBLE GAS

• Also known as Group 0 / inert/ stable 

• All element except Radon occurs in the atmosphere

• Monoatomic, colorless, & odorless gases under ordinary condition of temperature and pressure

• Valence: 0

GROUP VIIIA - NOBLE GAS

• ELEMENTS

Helium

Neon

Argon

Krypton

Xenon

Radon

Helium (He)

• Physical properties

• “Donald  duck” sound 

• 2nd lightest gas

Helium (He)

• toxicity

• Though inhalation 

• Donald duck sound

Helium (He)

• use

Carrier / diluent of medically important gases and component of artificial gas

artificial air

80% He + 20% O₂ (used in underwater diving)

Helium (He)

• container

brown

Neon (Ne)

For advertising

Argon (Ar)

• physical properties

Most abundant of all noble gas

Argon (Ar)

• use

Substitute for Nitrogen in providing inert atmosphere for pharmaceuticals

Krypton

• physical properties

(2nd) least abundant noble gas

Krypton

• use

Have inhalational anesthetic activity

Xenon

• Extinct 

• Investigational with inhalatory anesthetic activity

Radon

• aka

niton

Radon

• physical properties

• Synthetic noble gas 

• recovered from radioactive decay of Ra

Radon

• use

Used for treatment of Cervical cancer

GROUP VIIIB - FIRST TRIAD

• 1st triad

• Fe, Co, Ni 

• Valence +2, +3 

• The important oxidation states are +2, achieved by the loss of 2s electron & +3 in which an additional d electron is lost

2ND Triad / Light Triad

• Rh, Ru, Pd* 

• Ru complexes: anticancer

3RD Triad

• Os, Ir, Pt*

• Catalyst in finely divided steel

• Lindlar catalyst - Pd or Pt converting alkyne/alkene into alkane

• Magnetic properties are unique

Iron

• aka

Iron

• physical properties

• Distributed widely in nature

• Functions in divalent and trivalent states to form Iron (II) ferrous and Iron (III) ferric

• Most important element in engineering

Iron

• pharmacologic use: present in

• Hemoglobin (Fe in blood)

• Transferrin (transport form of Fe in the body)

• Ferritin (storage) 

• Cytochrome oxidase (Fe & Cu)

Iron

• pharmacologic use

• Enhance the absorption of Vitamin C and copper

• Hematinic - treatment of microcytic, hypochromic anemia (Iron Deficiency Anemia)

Iron

• toxicity

GIT distress & cardiac collapse

Iron

• antidote

deferoxamine

Mucosal block postulation by Hahn

Best known hypothesis of Fe absorption in Duodenum

Common ores

• Hematite (Fe₂O₃)

• Pyrite / Fool’s Gold (native FeS₂)

• Iron Stone (FeCO₃) in Chalybeate pills / Ferrunginous pills

Ferrous Sulfate (FeSO₄)

• aka

green vitriol

Ferrous Sulfate (FeSO₄)

Hematinic

Ferrous Sulfate (FeSO₄)

• side effect

constipation

Ferrous Gluconate (C₁₂H₂₄FeO₁₄)

• Brand name: Fergon 

• Advantage: Less irritating

Cast / pig Iron

From blast furnace (92-94% Fe)

Wrought iron

Removal of cast iron impurities (99.9% Fe)

Cementite / white cast iron

Solid solution of hard, brittle Fe carbide

Gray cast iron / graphite scales

Liquid Fe is run into sand molds & allowed to cool

Ferrous Fumarate (C₄H₂FeO₄)

Brand name: Toleron

Ferrous Carbonate (FeCO₃)

• aka

Ferrous Carbonate (FeCO₃)

hematinic

Ferric Chloride (FeCl₃)

• Astringent 

• Styptic 

• Reagent for detection of tannins

Basham’s Mixture

• Component: Iron + ammonium acetate 

• Astringent 

• Styptic

Ferric Ferrocyanide (Fe₄[Fe(CN)₅]₃

Prussian blue

Ferro Ferricyanide (Fe₃[Fe(CN)₆]₂

Turnbull’s blue

Cobalt (Co)

• physical properties

• (+) Permanent magnets, Vit B12 (cyanocobalamin, as Co²⁺; RBC & Hgb development)

• Enhances beer's foam quality (fd in Colt 45)

Cobalt (Co)

• pharmacologic use

• Essential in development of erythrocytes and hemoglobins

• Component of Vitamin B12

Cobalt (Co)

• deifciency

• Megaloblastic/ macrocytic anemia & pernicious anemia 

Treatment; cyanocobalamin

Cobalt Chloride (CoCl₂)

• aka

Lover’s ink, Sympathetic ink

Cobalt Chloride (CoCl₂)

Dessicator indicator

Nickel

• aka

old nick’s copper

Nickel

• physical properties

found in fossil fuels

Nickel

• use

used in fancy jewelries

Osmium

• physical properties

Heaviest / densest metal

Osmic Acid

Osmium Tertroxide

Staining microorganism for microscopic study especially electron microscopy

Ruthenium (Ru)

Ru complexes: used as anticancer

Iridium (Ir) Platinum (Pt)

Noble metals (low oxidation & reactivity)

Cisplatin

Cis-diaminedichloroplatinum 

• For prostate CA

Platinum (Pt) & Palladium (Pd)

• Catalyst in finely divided steel 

• Unique magnetic properties