Chemistry of p-Block Elements- Group 13

Gallium, Indium, and Thallium

Slide 1

• Group 13 elements: B, Al, Ga, In, Tl
• Also known as Boron group elements
• Tendency to form +3 oxidation state

Slide 2

• Electronic configuration of Group 13: ns^2 np^1
• Size of atoms increases down the group
• Ionization energy decreases down the group

Slide 3

• Gallium (Ga)
  • Atomic number: 31
  • Melting point: 29.76°C
  • Boiling point: 2204°C

Slide 4

• Indium (In)
  • Atomic number: 49
  • Melting point: 156.60°C
  • Boiling point: 2000°C

Slide 5

• Thallium (Tl)
  • Atomic number: 81
  • Melting point: 303.5°C
  • Boiling point: 1447°C

Slide 6

• Gallium (Ga)
  • Found abundantly in bauxite and zinc ores
  • Used in semiconductors, LEDs, and high-temperature thermometers

Slide 7

• Indium (In)
  • Extracted as a byproduct of zinc and lead refining
  • Used in semiconductors, low melting point solders, and touchscreens

Slide 8

• Thallium (Tl)
  • Obtained from flue dusts and byproducts of smelting processes
  • Used in electronics, infrared detectors, and as a rat poison

Slide 9

• Compounds of Gallium (Ga)
  • Gallium nitride (GaN) used in LEDs
  • Gallium arsenide (GaAs) used in solar cells and transistors

Slide 10

• Compounds of Indium (In)
  • Indium tin oxide (ITO) used in touchscreens
  • Indium sulfide (In2S3) used as a photosensitizer in solar panels

• Compounds of Thallium (Tl)
  • Thallium sulfate (Tl2SO4) used in insecticides
  • Thallium bromide (TlBr) used in infrared detectors

• Chemical properties of Group 13 elements
  • Prefer to form ionic compounds in the +3 oxidation state
  • Tendency to exhibit covalency in compounds
  • Formation of complex ions

• Boron (B)
  • Atomic number: 5
  • Melting point: 2076°C
  • Boiling point: 3927°C

• Boron compounds
  • Borax (Na2B4O7·10H2O) used in laundry detergents
  • Boric acid (H3BO3) used as an antiseptic and insecticide

• Aluminum (Al)
  • Atomic number: 13
  • Melting point: 660.32°C
  • Boiling point: 2519°C

• Aluminum compounds
  • Aluminum oxide (Al2O3) used in ceramics and as an abrasive
  • Aluminum hydroxide (Al(OH)3) used as an antacid and in cosmetics

• Group 13 Trends: Reactivity
  • Decrease in reactivity down the group
  • Alkali metals are more reactive than Aluminum
  • Aluminum is more reactive than Gallium

• Group 13 Trends: Electronegativity
  • Electronegativity decreases down the group
  • Boron is the most electronegative element in the group
  • Thallium has the lowest electronegativity in the group

• Group 13 Trends: Atomic Size
  • Atomic size increases down the group
  • Boron has the smallest atomic size
  • Thallium has the largest atomic size

• Applications of Group 13 elements
  • Bismuth alloys used as low-melting point solders
  • Aluminum used in construction, aerospace, and packaging industries

• Gallium (Ga)
  • Metal properties, but has a low melting point
  • Examples: Gallium arsenide (GaAs) used in solar cells, Gallium nitride (GaN) used in blue LEDs

• Indium (In)
  • Soft, malleable metal with a low melting point
  • Examples: Indium tin oxide (ITO) used in touchscreens, Indium sulfide (In2S3) used in solar panels

• Thallium (Tl)
  • Highly toxic, soft metal
  • Examples: Thallium sulfate (Tl2SO4) used in insecticides, Thallium bromide (TlBr) used in infrared detectors

• Chemical properties of Group 13 elements
  • All have three valence electrons
  • Tendency to form +3 oxidation state
  • Reactivity increases down the group

• Lewis acidity of Group 13 elements
  • Electron-deficient compounds
  • Examples: Boron trifluoride (BF3), Aluminum chloride (AlCl3)

• Boron compounds as Lewis acids
  • Boron trifluoride (BF3) used as a catalyst in organic reactions
  • Aluminum chloride (AlCl3) used in Friedel-Crafts reactions

• Reducing properties of Group 13 elements
  • Can reduce certain compounds by gaining an electron
  • Examples: Boron hydrides (BH3), Aluminum hydride (AlH3)

• Boranes (Boron hydrides)
  • Examples: Diborane (B2H6) used as a reducing agent, Borane-dimethyl sulfide complex (B(CH3)3:S) used in organic synthesis

• Aluminum hydride (AlH3)
  • Known as “alane”
  • Strong reducing agent, used in synthetic organic chemistry

• Summary of Group 13 chemistry
  • Gallium, Indium, and Thallium are important elements in various industries
  • Group 13 elements show a trend of decreasing reactivity and increasing atomic size down the group
  • Compounds of Group 13 elements have diverse applications in electronics, semiconductors, and agriculture