Inorganic Chemistry 1: Hydrogen, Group 1, and Group 2 Metals

Hydrogen

• Atomic structure: 1 proton and 1 electron
• Importance in theoretical chemistry due to simplicity
• Forms isotopes with differing physical and chemical properties
• Deuterium (D) is heavier than protium (H)

Hydrides and Hydrogen Bonding

• Hydride ion (H-) formed by electron attachment to H atom
• Hydrides of s-block metals (excluding Be) can be made by heating metal with H2
• Hydrogen bonding: attractive force between H atom bonded to electronegative atom and another electronegative atom with lone pair electrons

Isotopes of Hydrogen

• Deuterium (D) and Tritium (T) are heavy isotopes
• D2O (heavy water) has stronger hydrogen bonding than H2O
• Main uses of D2O: treating metals that form amphoteric hydroxides, reacting metal hydrides with water

Di-Hydrogen

• Industrial applications: Haber process, hydrogenation of unsaturated fats, production of organic compounds
• Future potential as alternative energy source (hydrogen economy)

Reactivity of Hydrogen

• Not very reactive under ambient conditions due to strong H-H bond
• Can explode when sparked with oxygen (qualitative test for H2)

Alkali Metals (Group 1)

• Members: Li, Na, K, Rb, Cs, Fr
• Electronic configuration: ns1
• Physical properties:
  • Soft, silvery-white metals
  • Low melting points
  • High reactivity

Alkali Metal Properties

• Reactivity: lose one electron to form a cation
• Electrolysis of fused halides or hydroxides to produce alkali metals
• React vigorously with water: M + H2O → MOH + 1/2H2

Sodium (Na) and Potassium (K)

• Most abundant alkali metals in Earth's biosphere
• Extraction: electrolysis of NaCl (Downs process) and KCl
• Uses:
  • Na: manufacturing of NaOH, Cl2, and Na2CO3
  • K: fertilizers, manufacturing of K2CO3 and KNO3

Lithium (Li) and Caesium (Cs)

• Lithium:
  • Used in alloys and glasses
  • Important in the treatment of manic-depressive disorders
• Caesium:
  • Important in atomic clocks and electronics
  • Has a short half-life of 21.8 minutes

Alkaline Earth Metals (Group 2)

• Members: Be, Mg, Ca, Sr, Ba, Ra
• Electronic configuration: ns2
• Physical properties:
  • Greyish-white or silver-colored metals
  • Low melting points
  • High reactivity

Be and Mg

• Be:
  • Lightest metal, non-magnetic, high thermal conductivity
  • Used in high-speed aircraft and satellites
• Mg:
  • Important in the manufacturing of Mg/Al alloys
  • Used in aircraft and automobile body parts and lightweight tools

Calcium (Ca) and Strontium (Sr)

• Ca:
  • Essential for green plants (chlorophyll)
  • Used in construction, paper manufacturing, and water treatment
• Sr:
  • Used in fireworks and pyrotechnics
  • Important in nuclear medicine