Group IIIA-VB

Week 9 - Midterm

Overview

  • Focus on Group Properties of Elements

  • Emphasis on use, physical, and chemical properties for pharmacy.

Group IIIA Elements

Overview

  • Composed of: Boron (B), Aluminum (Al), Gallium (Ga), Indium (In), Thallium (Tl).

  • Key points:

    • Aluminum is the most common metal and the third most abundant element in the Earth's crust (after Oxygen and Silicon).

Properties

  • Boron: Non-metal (termed as metalloid), exhibits mixed characteristics.

  • Group exhibit ionic character.

  • Metals are oxidized when heated in air but stable at ordinary temperatures.

  • Oxides can be reduced back to metals.

  • Reactivity:

    • Reacts readily with sulfur and halogens.

  • Common oxidation state: +3.

    • Hydroxides exhibited amphoteric properties, except top (B) and bottom (Tl) elements. Aluminum hydroxide is notable.

Identity Tests for Ions

  • Boron (BO3^3-):

    • Reaction with acids (CH3OH + H2SO4) produces a green-bordered flame.

    • Turmeric paper test results in brownish-red that turns greenish-black in alkali.

  • Aluminum (Al^3+):

    • Reaction with NH3 produces a white gelatinous precipitate of Al(OH)3 and a red lake with aluminon.

    • Thenard's Blue Test involves reactions yielding blue ash.

Group IIIB Elements (Scandium Subgroup)

Overview

  • Includes Scandium (Sc), Yttrium (Y), Lanthanides (atomic numbers 90-103), etc.

  • Characterized by increasing metallic character with increasing atomic number.

Properties

  • Common oxidation states: +3, occasionally +2 or +4 (especially Cerium).

  • Lanthanides occur in mixtures that are difficult to separate; Actinides are synthetic and radioactive.

Group IV Elements (Carbon Family)

Overview

  • Elements: Carbon (C), Silicon (Si), Germanium (Ge), Tin (Sn), Lead (Pb).

    • C and Si: Non-metals

    • Sn and Pb: Metals

    • Ge: Metalloid

Properties

  • Exhibit oxidation states of +2 and +4.

  • Carbon:

    • Fundamental to organic compounds, reducing agent in metal preparation.

    • Inert at room temperature but reactive at elevated temperatures.

  • Silicon: Found abundantly in nature as silica (SiO2).

  • Tin (Sn) and Lead (Pb) properties:

    • Common amphoteric oxides: SnO2 and PbO2 with relevant reactions yielding ions and complexes.

Identity Tests for Ions

  • Carbon-containing ions (CO3^2- and HCO3^-):

    • Effervescence with acids; different phenolphthalein results.

  • Miscellaneous tests for various anions (e.g., $ ext{C}_2 ext{O}_4^{2-}$, $ ext{C}_6 ext{H}_5 ext{O}_7^{3-}$).

Group IVB Elements (Titanium Subgroup)

Overview

  • Elements: Titanium (Ti), Zirconium (Zr), Hafnium (Hf).

Properties

  • Exhibit oxidation states +2, +3, and +4.

  • Their compounds with tetravalent forms lack color, while lower-valence states are often colored.

  • Titanium Dioxide (TiO2) important for its covering power as a pigment.

Group VA (Nitrogen Family)

Overview

  • Includes: Nitrogen (N), Phosphorous (P), Arsenic (As), Antimony (Sb), Bismuth (Bi).

Properties

  • N and P: Non-metals; others range from metalloids to metals.

  • Common oxidation states include -3 to +5.

  • All react with hydrogen to create hydrides (e.g., NH3, PH3).

  • Phosphorous exists in two allotropic forms (white and red).

Identity Tests for Ions

  • Tests for specific ions like NH4+ and various anions (e.g., CN-, NO2-, NO3-, etc.), utilizing compound reactions yielding precipitates or color changes.

Group VB Elements (Vanadium Subgroup)

Overview

  • Elements: Vanadium (V), Niobium (Nb), Tantalum (Ta).

Properties

  • Capable of forming compounds with oxidation states of +2 and +5.

  • Typically colored compounds at +2 state.

  • Known for good reducing action; Tantalum has specific applications in medicine for corrosion resistance.