Chemistry Chapter on Atomic Structure and Oxygen

Group VA - The Nitrogen Family

• Elements: Nitrogen (N), Phosphorus (P), Arsenic (As), Antimony (Sb), Bismuth (Bi)

Chemical Properties

• Outer electron configuration: s²p³
• Sharing of 3 or 5 outer electrons → 3+ & 5+ oxidation states
• Also exhibit a -3 oxidation state (except Bismuth - Bi)
• Bismuth does not readily accept electrons
• Compounds of Sb, As, P, and N can accept three electrons to pair up electrons in outer p orbitals forming antimonides, arsenides, phosphides, and nitrides
• Compounds are covalent

Hydrides

• M + H₂ → Hydrides
• Examples:
  • Ammonia (NH₃)
  • Phosphine (PH₃)
  • Arsine (AsH₃)
  • Stibine (SbH₃)
  • Bismuthine (BiH₃)
• All except ammonia (NH₃) are highly flammable and poisonous.

Nitrogen Cycle

• Microbes "fix" nitrogen in nodules on the roots of pulse crops.

Nitrogen Fixation

• Used to making ammonia

Nitrogen Gas

• Used as a container
• Used as a coolant

Liquid Nitrogen

• Used as a refrigerant
• Used in cryogenics

Other Information

• N₂O ("Laughing Gas")

  • General anesthetic (inhalational)
  • Not used alone – causes diffusion hypoxia
  • Blue cylinder

• N₂O₃

  • Gas (brown color or pale blue liquid)

• NO₂

  • Brown gas

• Phosphorus (P)

  • Normally a white waxy solid
  • Colorless and translucent
  • Stored under water
  • "St. Elmo's Fire"
  • Light carrier (match)
  • Apatite:
    • White/Yellow – Poisonous
    • Red – Non-poisonous
    • Use in preparation of matches

• Allotropic Modification of Phosphorus: -White Phosphorus: P₄ tetrahedron -Scarlet Phosphorus: made by heating PBr₃ (phosphorus tribromide) with Hg at 240°C -Violet Phosphorus: heating P with a small quantity of Na at 200°C -Metallic or Black Phosphorus: heating P with Pb at 530°C

• Arsenic (As) -Toxic, protoplasmic poison -Lewisite metal -Anti-syphilis discovered by Paul Erlich -Component of Salvarsan, Arsphenamine, Compound 606 -Antileukemia -Preparation of various insecticides -Sources: Arsenopyrite (FeAsS), Cu Aceto Arsenate, "Paris Green", K Arsenite, Fowler's Solution, Donovan's solution, AsI³ (HgI²) -Gutzeit Test: presence of arsenic in a light brown spot is a result in a filter paper moistened with silver nitrate solution -Symptoms of Arsenic poisoning: - Melanosis, Bowens disease, facial oedema, Hyperpigmentation, skin cancer, Dimness of vision, Tremor, Anorexia, Nausea, Vomiting, Diarrhoea, Weight loss, Perforation of nasal septum, Chronic laryngitis, Bronchitis

  • Antidote: BAL

• Antimony (Sb) -Sources: Senarmontite (Sb₂O₃), Valentinite (Sb₂O₃), Cervantite (Sb₂O₄), Antimony Glance (Stibnite, Sb₂S) -Pharmaceutical use: expectorant, emetic, anthelmintic -Antimony Potassium Tartrate ("Tartar Emetic") - Component of Brown mixture - Emetic, Expectorant, Treatment of Schistosomiasis -Babbit Metal: - Alloy of Antimony (80% Tin and 20% Antimony)

• Bismuth (Bi) -Sources: Bismuthite (Bi₂S₃), Tetradymite (Bi₂Te₃), Bismite (Bi₂O₃) -Pharmaceutical use: - "Beautiful meadow" - Use in silvering of mirrors -Astringent, antiseptic, internal protective

  • Adverse effects:
    • Blue black lining of gums
    • Black stools
  • antidote: BAL -Bismuth Subcarbonate: Antacid, antiseptic, astringent; 60 grams render alimentary canal opaque to x-ray
  • Bismuth Subgallate: Active ingredient in Devrom®, an over-the-counter FDA-approved medicine -Bismuth Subnitrate ("White Bismuth"): used in the treatment of ulcer and inflammation of the GIT; Incompatible with tragacanth -Milk of Bismuth ("Bismuth Cream"): Bi(OH)₃ + Bismuth Subcarbonate, for H. pylori; internal protective for gastric ulcer

• Identification and Tests of Group VA elements:*

• NH₄⁺ -Nessler's reagent (alkaline K₂HgI₄): orange ppt of HgO.HgNH₂I (iodide of Millon's base) -Heated with strong alkali: evolution of NH₃ detected by its characteristic odor and change red litmus paper to blue

• CN^- -AgNO₃: white ppt of AgCN (silver cyanide); insoluble in HNO₃ -Hg₂(NO₃)₂: black ppt of metallic Hg

• Sb³⁺ -H₂S: orange ppt of Sb₂S₃ soluble in Na₂S -Al metal: black ppt of metallic Sb insoluble in NaOBr reagent

• Bi³⁺ -H₂S: brownish black ppt of Bi₂S₃ insoluble in Na₂S reagent -Na₂SnO₂: black ppt of metallic Bi

• SO₃^2- -dil. H₂SO₄: evolves SO₂ [odor of burnt sulfur]

• SO₄^2- -dil. H₂SO₄: NR; BaCl₂: white ppt of BaSO₄, which is insoluble in all acids

• S₂O₃^2- -dil. H₂SO₄: evolves SO₂ [odor of burnt sulfur]; KMnO₄ or I₂ solution: the solutions are decolorized

• Cr³⁺ -NaOH: grayish green ppt of Cr(OH)₃ which will dissolve in excess of the alkali to form a green solution, NaCrO₂. -When an oxidizing agent like Na₂O₂ is added, it turns yellow due to Na₂CrO₄

• CrO₄^2- -BaCl₂: yellow ppt of BaCrO₄ -AgNO₃: brownish red ppt of Ag₂CrO₄ -H₂O₂ and ether → blue ethereal layer due to perchromic acid (Perchromic Acid Test or Vanishing Blue Test)

Group VB - The Vanadium Subgroup

• Elements: Vanadium (V), Niobium (Nb), Tantalum (Ta)
• Oxidation states: 2+ through 5+
• Lower valence states tend to be unstable (except in the elements with the highest atomic number)
• Acidity of oxides, basicity of hydroxides generally decrease with increasing atomic number (for V)
• Compounds in lower oxidation states are colorful
• Inert to chemical action in finely divided form (V, Nb, Ta)
• Tantalum (Ta) -Unaffected by bloody fluids -Use in sheet form for surgical repair of bones, nerves, tissues -Corrosion resistant -Source: Tantalite
• Vanadium (V)
  • Hard, silvery-grey, ductile and malleable transition metal -Source: Carnotite, Patronite, Vanadinite
• Niobium (Nb) -Soft, grey, ductile transition metal -Often found in pyrochlore mineral (main commercial source) and columbite

Group VI - The Chalcogens

• Elements: Oxygen (O), Sulfur (S), Selenium (Se), Tellurium (Te), Polonium (Po)
• Properties: Primarily non-metals, but some are metalloids; most are highly electronegative, exist primarily in their diatomic form (O₂ etc.), tend to form compounds of the form M₂X (where M is metal and X is a chalcogen)

Other Information

• Oxygen (O) -Properties: -Most abundant element in the Earth's crust. -Common element known to ancients as brimstone or burning stone. -Found on Earth as a free element/in combined form (metal sulfides/sulfates). -“Dephlogisticated Air” and “Empyreal Air”. -Most abundant element. -Nonmetallic element -2nd most electronegative element -Responsible for oxidative changes in paints, fats, fixed oils. -Green cylinder. -Allotropes: Ozone (O₃), Oxygen (O₂), Nascent Oxygen ([O]) -Oxygen Requirements: -Anoxic – inadequate O₂ tension in air -Anemic – decrease hemoglobin -Histotoxic – tissue or cell oxidation -Stagnant – blood circulation is retarded -Uses: Treatment of hypoxia

• Sulfur (S) -Properties: - Known to ancients as brimstone/burning stone -Common element on Earth’s crust—found free or in combined form (sulfides & sulfates). -Sources: FeS₂ – Iron Pyrite, PbS – Galena, HgS – Cinnabar, ZnS – Zinc blend, CaSO₄ • 2H₂O – Gypsum, BaSO₄ - Heavy spar -Allotropes: Rhombic, Monoclinic, Mobile, Viscous, Plastic/Amorphous, Sulfur Vapor -Different Forms: Precipitated sulfur, sublimed sulfur -Uses: Preparation of scabicidal and keratolytic ointments and lotions, stimulant cathartic, stimulant in alopecia, fumigate (SO₂), Depilatory (sulfides), Keratolytic (SrS), Antiseborrheic (CdS) -Sulfuric acid ("Oil of Vitriol") -Sulfonating agent -Dehydrating agent -Sodium Thiosulfate: use in photography, treatment for ringworm, antidote for cyanide and iodine poisoning

• Hydrogen Sulfide -"Aitch-tu-es-gas" -Reducing agent, precipitating agent of metal ions -Rotten egg odor

• Sulfur Ointments
  -Precipitated sulfur -Liquid petrolatum -White ointment -Scabicide -Parasiticide

• Selenium (Se) -"Moon" -Trace element -Antioxidant -Synergistic with vitamin E -Toxic when taken internally -Use in the manufacture of photocopying machines -Catalyst in nitrogen determination -Selenium Sulfide: Active constituent of Selsun Blue; Anti-seborrheic

• Polonium (Po)

  • Radioactive isotope from the decay of actinide elements -Identification Tests: -h₂S: salmon or flesh colored ppt of MnS -NaBiO₃: purple solution of HMno₄ (permanganic acid)

Group VII-A - The Halogens

• Elements: Fluorine (F), Chlorine (Cl), Bromine (Br), Iodine (I), Astatine (At)

Other Information

• Halogens: -Most active family of nonmetals -Exist as diatomic molecules

  • Never free in nature -Oxidation property decreases with increasing atomic number

• Fluorine (F) -Physical state: Pale yellow gas -Chemical properties: Most electronegative element, strongest oxidizing agent, reacts violently with nonmetals -Natural Sources: Fluorospar (CaF₂), Fluoroapatite (3Ca₃(PO₄)₂Ca(CIF)), Cryolite (Na₃AlF₆) -Poisoning: Fluorosis (mottled enamel and abnormal bone growth) -Identification tests: Etching test (H₂SO₄); AgNO₃: no ppt -Compounds and uses: -NaF - 2% in 4 application -SnF₂- 8% freshly preparation -Dichlorofluoromethane (Freon): refrigerant & propellant

• Chlorine (Cl) -Physical state: greenish-yellow gas -Chemical properties: Predominantly an anion, does not readily react with carbon -AKA Dephlogisticated muriatic acid -Found in large quantities as sodium chloride (NaCl) in seawater/land deposits -Identification tests: Various tests listed above -Uses: H₂O Disinfictant, various compounds

• Bromine (Br) -Physical state: reddish brown fuming liquid -Chemical properties: toxicity—Bromism (skin eruption, psychosis, weakness), Treatment – NaCl or NH₄Cl -Identification tests: AgNO₃: yellow ppt of AgBr insoluble in HNO₃; KMnO₄, H₂SO₄, chloroform: orange to brown layer due to the liberation of Br₂ -Compounds and uses: Koppeschaar's solution - 0.1N Bromine solutionn; Sedative; used in iodometry

• Iodine (I) -Physical state: grayish black solid, violet-colored vapor -Chemical properties: Combines directly many elements; reacts with most metals and some nonmetals to form iodides -Identification tests: AgNO₃: yellow ppt of AgI insoluble in HNO₃; KMnO₄, H₂SO₄, chloroform: violet layer due to the liberation of I₂. -Uses: Expectorant, antiseptic, antimicrobial -lodine Preparations: -Strong iodine solution/ Lugol's solution -Saturated solution of potassium iodide (KISS)

• Astatine (At) -Least electronegative element -Only synthetic halogen -Only radioactive halogen -Only metallic halogen

Group VII-B - The Manganese Subgroup

• Elements: Manganese (Mn), Technetium (Tc), Rhenium (Re)

Other Information

• Manganese (Mn) -Only metal of pharmaceutical importance in this group -Occurs mostly as oxide (MnO₂) -Difficult to prepare in pure state -Used in alloy steels -Physical state: Hard, silvery-grey metal that resembles iron -Chemical Properties: exhibit oxidation states of 2+ to 7+ -2+ Compounds are good reducing agents -MnO₄^- (permanganate) is a good oxidizing agent -Salts: Hausmannite (complex oxide containing di- and tri-valent manganese); Braunite (silicate mineral containing di- and tri-valent manganese) -Identification tests: H₂S: salmon or flesh colored ppt of MnS; NaBiO₃: purple solution of HMnO₄ (permanganic acid)
  -Compounds and use: -Manganese Sulfide: Trace element; cofactor in CHON synthesis for riboflavin; phosphorylation; fatty acid and cholesterol synthesis; Similar to parkinsonism -KMnO₄: Mineral chameleon; oxidizing agent; volumetric soln in permanganometry

• Technetium (Tc) -1st element produced artificially

  • Used in preparation of radiopharmaceuticals -Diagnostic agent

• Rhenium (Re) -Extremely rare -Knowledge of its properties is available

Group VIII-A - The Noble Gases

• Elements: Helium (He), Neon (Ne), Argon (Ar), Krypton (Kr), Xenon (Xe), Radon (Rn)

Other Information

• Characteristics: -Colorless, odorless, tasteless, nonflammable gases -Traditionally labeled "group 0" because they are believed not to bond with other atoms. -Uses: -Neon: Advertising purposes; 2nd lightest noble gas; bright reddish orange light -Argon: Most abundant inert gas; present in air, natural gas, occluded minerals, dissolved in oceans and fresh waters; substitutes nitrogen; inert atmosphere for pharmaceuticals -Krypton and Xenon: Used in flash lamps and arc lamps -Radon: Inert gas given off by radium salts as decomposition product; It is itself radioactive